We are back where it all began: 5500 34th Street West, Bradenton, Florida. This is where six-year-old Masha Sharapova and her father Yuri turned up 24 years ago, begging to be given a chance at the tennis club for rich kids run by the legendary coach Nick Bollettieri.

You can still smell the privilege. A security man at the imposing gates looks at my two carrier bags and assumes I’m homeless: “Excuse me, what are you doing here?” I tell him I’m here to interview Sharapova. He looks me up and down with thinly disguised contempt, and asks if I can move away from the entrance. “Or at least hide your bags. The first thing our guests can see as they drive in is your bags.” I begin to see how alien this must have felt for the Sharapovas, who arrived in America armed with only $700 and a dream.

How times change. After winning a career grand slam (all four major titles: Wimbledon, and the US, Australian and French Opens, the latter twice), 11 consecutive years as the highest paid female athlete on the planet with total earnings estimated by Forbes at $285m, Sharapova is back at the IMG Academy, training for the US Open, her first major tournament since she was banned in March 2016 for taking the controlled drug meldonium.

Appropriately enough, we meet in the boardroom; Sharapova is as famous for her business sense as for her tennis. She bounds into the room in her training gear: fresh-faced, no makeup, alert, looking and sounding like an all-American girl. The most surprising thing is her size. Sharapova is 6ft 2in, arms and legs like tentacles, broad shoulders, massive hands. On screen (and despite the ferocity of those famous on-court grunts), she can appear slight and underpowered against her great rival Serena Williams; but in her own way, she is every bit as imposing.

“I love this place,” she says of the academy. “It’s my home base. This is where I came on my second day in America.” She smiles. “I can only do two weeks, though, then I start losing my mind. It’s really quiet and there is not much going on – which is great for training.”

As you might expect of somebody who likes a lot going on, Sharapova has not wasted her time away from the court. She took a class at Harvard Business School in global strategic management, spent 10 days in London studying leadership, interned at an advertising agency and spent a week shadowing the commissioner of the National Basketball Association, Adam Silver. She has also written her autobiography, Unstoppable, a fascinating and well-written (with the help of Vanity Fair journalist Rich Cohen) insight into her struggles, triumphs, obsession with Williams, Russian pessimism and the roots of that famous haughtiness.

I had every opportunity to change professions, or to live the rest of my life on a holiday, but it never crossed my mind

What makes the book so unusual, and true to Sharapova, is that she makes little attempt to endear herself to the reader. I tell her I like the fact that she admits she never wants to befriend fellow players; she regards it as fake when they are rivals. “Right,” she says. “Is that a question?”

The book starts and ends with the 2016 drugs ban: her horror at discovering that she had been taking meldonium for a month after it had become prohibited (in January 2016); and what she regards as her vindication when the court of arbitration for sport ruled last October that she did not use it as a “performance-enhancing product, but for medical reasons”. Her ban was reduced from two years to 15 months after the court ruled there was no intent to violate the new regulations: “Under no circumstances, therefore, can the player be considered to be an ‘intentional doper’.”

Much of Sharapova’s memoir is about growth – physically, from the six-year-old who hung from beams to make herself grow, to the gawky teenager, to the powerhouse who became world No 1. (At one point, Sharapova wonders if her height is down to the Chernobyl nuclear disaster: her mother was pregnant with her soon after, and “continued to drink the water and eat the vegetables”; years later, on visits to her grandmother’s house nearby, she was “amazed by the huge forest mushrooms. Everyone said it was caused by radiation, which makes you wonder.”)

But she is even more interested in other forms of growth, which is what she wants to talk about now. “When you don’t feel you’re on top of the world, how are you going to make yourself grow? Who are you going to surround yourself with who will make you feel better and stronger? When you’re at the top, you feel pretty good.”

So who has she surrounded herself with since the ban? “The same people I’ve had throughout my whole career. I’ve been really fortunate. There are not many who have come and gone in my life.”

‘I made a huge mistake’: revealing she had failed a drug test in 2016. Photograph: Robyn Beck/AFP/Getty Images

Has she learned much about herself? “I learned how resilient I can be. How much patience I have. How much dedication I still have. I had every opportunity to change professions, or to live the rest of my life on a holiday, but it never crossed my mind. I was on the court for the first four, five months, when I didn’t know when I’d be back. I also found a new understanding of what my body was capable of in my late 20s – now 30. I never thought, as a teenager or in my younger 20s, that my body would be able to take on the workload I’m still able to.”

When Sharapova announced a surprise press conference in March 2016, people assumed she was retiring. But, dressed in sombre black, and exuding gravitas and contrition, she revealed she had failed a drug test: “I take full responsibility for it. I made a huge mistake. I let my fans down, I let the sport down... I know with this I face consequences and I don’t want to end my career this way, and I really hope I will be given another chance.”

It was one of the most dramatic moments in tennis history, and Sharapova appeared as in control as ever. She said she had been taking meldonium (which she knew by its trade name Mildronate) for 10 years, because of an irregular heartbeat and a family history of diabetes. Meldonium is only distributed in Baltic countries and Russia: in 2015, of 4,316 samples drawn from Russian athletes, traces of meldonium were found in 17% of them – almost eight times the level internationally. A 2012 report from the Baltic Sport Science Conference concluded that the drug “is recommended for use as a pharmacological remedy that increases the physical work capabilities of athletes”.

How did she feel when she received the email saying she had failed the test? “For the first hour, I thought it was a mistake.” And then? “I said, how did I not know? How did my team not know? How did no one notify me? I started asking questions.”

In fact, she had been notified in an earlier email, but neither Sharapova nor her team had read it. She would almost certainly have received a clearer warning if she had told the World Anti-Doping Agency (Wada) that she was taking meldonium; but, despite registering other approved drugs with the agency, she had not declared it for years.

In 2012, Sharapova had parted ways with her Russian doctor Anatoly Skalny, who originally prescribed the meldonium in 2006 – ironically, because she disliked the amount of medication he wanted her to take. After that, she delegated responsibility to her agent, Max Eisenbud, a man who had helped her make hundreds of millions of dollars, but who had no medical experience. He missed the crucial emails, and had failed fully to declare to Wada.

Was she angry with him? “I could have got pissed off with a lot of people, and that would have been fair for me, but it wouldn’t have changed anything.” Eisenbud remains her agent. Was she pissed off with herself? “Absolutely. If there’s one person to get pissed at, for sure that would begin with myself.”

I ask if she thinks she can regain her reputation. “I don’t think that’s a question that you can answer while sitting at a table. Everyone is entitled to an opinion, and I believe, ultimately, that’s what creates a reputation. For one tough opinion, one critical opinion, there are hundreds of incredible opinions.” What she means is that, while the media and other players might be tough on her, she will always have her fans.

Have lots of people been nice to her since the ban? Sharapova smiles – she has a lovely smile. “That’s one of the biggest reasons I’ve been able to come back.” What have they said? “That they can’t wait to see me return. It felt very personal, whereas before it was, ‘Can I have your autograph?’ or, ‘Can I take a picture?’ I just found people’s motive for coming up to me was more a message of support, not wanting something from me, which was really heartwarming. You encounter one instance of that, and it’s 20-30 seconds of your day, and it brings you up the ladder.”

In the past, she seemed to regard fans as irritants. “I grew a completely new understanding. When young girls and boys would say, I want to be like you, I would think, ‘No, you want to be better than me.’ I didn’t want the responsibility of being a role model. Maybe it was a selfish thing.”

And that has changed? “Absolutely. I understand now from the fan’s point of view – that they live, that they breathe, that they have a life of their own and you are able to change their day, change their mind, change their mindset, to change how they wake-up in the morning and if they’re happy or not. That I never understood. Or never made the effort to.” It’s an astonishing, and rather brave, admission that it’s taken till now to realise her fans are living, breathing people.

***

Hard and flat, hard and flat, hard and flat. By the time Sharapova was four, she was a tennis-playing metronome. She would hit every shot against a wall at the same height, at the same pace, at the same spot – and she could do it forever.

Hard and flat became her mantra, and reveals so much about her: the strengths that enabled her to win five major tournaments (power, discipline, stamina) and the weaknesses that have so far restricted her to the five (an inability, especially early on, to vary her game: all back-of-court winners, a refusal to come to the net).

When Sharapova was six, her coach told her father that she was to tennis what Mozart was to music, and that she could be the best in the world – but that she would never fulfil her potential in 20th-century Russia. A few months later, her father managed to get together enough money to fly her to a tennis coach in Moscow, where she was spotted by Martina Navratilova. That was when Yuri decided to give everything up – job, Russia and, temporarily, his wife – to make a new life for their daughter in America.

Does she think Serena is as obsessed with her? 'There’s a level of intensity that comes out more ferociously against me'

When they arrived at Bollettieri’s academy, young Masha (she became Maria because she disliked the way everyone mispronounced her name as Marsha) was refused a scholarship. She was too young, but Bollettieri allowed her to train there. After a few months, she was kicked out; she was beating children three or four years older and their parents did not like it, when she wasn’t even paying for the privilege. According to Sharapova, they started spreading rumours that Yuri had kidnapped her from Russia. Bollettieri didn’t want the bad publicity, and asked them to leave. She briefly found another coach but a few years later, when she was nine, Bollettieri invited her back on a scholarship.

For nearly three years, Sharapova did not see her mother, who eventually joined them in Florida in 1996. Until she boarded at Bollettieri’s academy, Maria and Yuri shared the same bed; in the book, she says they slept so close that she shared his dreams. In fact, she spent much of her childhood surrounded by alpha males, all of whom were brutally direct with her. She has been sponsored by the sports agency IMG since she was 11. When they asked Yuri how much he needed, he said $50,000 a year; the agency told him $100,000 was a more realistic figure. So if she now treats herself as a precious commodity, perhaps it’s inevitable: right from the start, so much has been invested in her.

She didn’t fit in at Bollettieri’s academy. She says the other girls liked to gossip and talk about boys, while the only thing she was interested in was getting to the top. In her book, she is fabulously catty about being given fellow boarder Anna Kournikova’s cast-offs. Most people would be delighted to get the Russian star’s hand-me-downs, I say. She raises her eyes to the ceiling. “I didn’t even have a choice. I still don’t like leopardskin prints. It haunts me to this day.”

One day, the Williams sisters, already regarded as future world-beaters, visited the academy. While the other students were desperate to meet the two incipient stars, Sharapova was too proud, so she hid in a shed and watched them play through a hole in the wall. As far as she was concerned, the Williams sisters just stood in the way of her ambition. At 15, she reached the final of Junior Wimbledon – the same year Serena won the senior event for the first time, aged 20. Sharapova was invited to the winner’s ball, where the tradition is for everybody to stand for the winners of the senior tournament as they enter the room. Sharapova writes that she could not bring herself to do so; there was just “a single thought in my head: ‘I am going to get you.’”

At the age of 17, on only her second appearance at Wimbledon, she won the senior tournament, beating the odds-on favourite Serena. It was a wonderful performance: fearless, relentless, hard and flat. The two players went on to have one of the great rivalries in tennis – not so much on court (Serena has dominated, winning 19 out of 21 matches), but off. They competed over popularity, column inches, wealth, endorsements (Serena has earned far more prize money, but Sharapova is the undisputed queen of endorsements, and therefore wealthier).

Hugging Serena Williams after the 2004 Wimbledon final – aged just 17, Sharapova won in straight sets. Photograph: Getty Images

In her book, Sharapova writes that when she returned to the locker room after her 2004 Wimbledon victory, she saw her opponent crying, and that Williams has never forgiven her for it. She dedicates page after page to Serena. When Serena misses a shot, she writes, she tends to fall to the ground to show that she has beaten herself, rather than been beaten by an opponent; and she is voluble on court to put off the opposition (Sharapova’s grunt has also been called a distraction tactic, as has her famous “death stare”, and habit of turning her back on the server to make them wait). But she bitches about how Serena hugged her on court after her surprise Wimbledon victory (what’s wrong with a handshake?). Another time, when Serena heard that Sharapova had got engaged (to basketball player Sasha Vujačić), she produced a ring of her own and told her that she, too, had just got engaged.

Maybe Serena was trying to bond with you, I suggest. Sharapova gives me a sceptical look. “She had found out I was engaged and congratulated me on my engagement – sarcastically! Then she pulled out a ring from this pouch, and I’m not aware if she’s competing with the fact that she’s also engaged or… I don’t know.’’

Sharapova has always made it clear how much she respects Serena as a player: why not as a person? “There are definitely choices in her words, things that she’s chosen to talk about that weren’t correct in the past.” Such as? “One of the interviews. When you start talking about family and other people you don’t know anything about, that’s when I put the brakes on. Those comments weren’t necessary.” This appears to be a reference to an interview Serena gave to Rolling Stone in 2013, in which she joked on the phone to her sister about a top-five player “who begins every interview with, ‘I’m so happy. I’m so lucky’ – it’s so boring. She’s still not going to be invited to the cool parties. And, hey, if she wants to be with the guy with a black heart, go for it.” At the time, Sharapova was dating Serena’s ex, tennis player Grigor Dimitrov. Williams later apologised.

Does she think Serena is as obsessed with Sharapova as she is with her? “I think it goes back to that match [the first Wimbledon final]. Her mindset really changed. There’s definitely a level of intensity and competitiveness that comes out much more ferociously against me than other opponents.” Or perhaps Sharapova freezes when she plays her? “Freeze?” she looks at me as if she doesn’t comprehend the word. Do you not play your best against her? “I think I could definitely give my best more often.”

The one area where Sharapova has always had the upper hand is sponsorships: incredibly, since her ban, she has lost only one major endorsement (excluding a temporary suspension by Nike); she earned $20m (£15.5m) last year, despite not playing a match. As well as selling other people’s products, she has her own candy brand, Sugarpova. Her critics say a top athlete should not encourage children to eat unhealthily. Is that fair? “I understand where they’re coming from, but everybody likes sweets, whether you’re an athlete or not. And there are different forms of sweets, natural sweets and not natural sweets. There’s a good type of sweet and a not good type.”

Are hers the good type? “They’re getting there. The chocolate is all natural ingredients.” So she is responding to the criticism? “No!” she replies, appalled. “It’s an evolution of the industry. The candy industry itself is going into natural ingredients. The dark chocolate is 70%. It’s delicious.”

Sharapova has lived in America for 24 of her 30 years. Does she feel more American or Russian? “In my home, I feel very much Russian. At home, I speak Russian. But outside of it, I feel very much American. I love this country and I’ve accommodated myself to the people. I love the opportunities it brings. But, from a feeling and mentality standpoint, to the directness with which I speak around my friends and family, I think a lot of that comes from my Russian heritage.”

Her comeback in this year’s US Open. Photograph: Elsa/Getty Images

What does she think of Donald Trump? “I’m not a fan of politics,” she says tersely. But you can dislike politics and still have an opinion? “I’ve learned in life that it’s better to form opinions when you know facts. I don’t know enough facts about politics to have a sufficient opinion.”

Although she could not imagine returning to Russia, she does not feel rooted in America. “I’ve spent all my life living out of suitcases, and even though I have a home here in Florida and a home in California, I don’t feel this is my place. I’m not attached to things.”

I ask about life after tennis. “Kids,” she says, instantly and warmly. In the book, she talks about how difficult it is to sustain a relationship: boyfriends have found it difficult to accept that she was more successful than them, particularly, she says, her former fiance, Vujačić.

Is she seeing anybody now? “Not consistently, no.” She becomes surprisingly giggly.

What does that mean – one man inconsistently, or a lot of men occasionally? “Don’t ask me that. Hahaha! Tape’s going off. I’m pressing stop. See, now I become shy. I’ve definitely been on some interesting and fun dates that could potentially lead to something in the future.” Names, please? “No! God, no!’” She says she’d find it hard to settle down while still competing. “I’ve had a difficult time with understanding balance. I’ve always thought balance is 50/50. And if you work so hard to be good at something, but you’re only able to give it 50% – I don’t know if I want to look back and feel regret.”

As for the immediate future, she is focusing on her tennis. In the first rounds of the US Open, she proved she is still a force to be reckoned with, knocking out number two seed Simona Halep, before losing to Anastasija Sevastova in the fourth round. But her return has been anything but easy. She has been injured for much of the year. She was expected to play at the French Open in May, but was refused a wildcard: wildcards are generally given to big draws, or players coming back from injury who have lost their world ranking. Few players have offered her their support. In April, the Canadian player Eugenie Bouchard told a reporter, “She’s a cheater, and I don’t think a cheater in any sport should be allowed to play that sport again.”

With her father Yuri in their first few days in Bradenton, Florida. Photograph: Courtesy Unstoppable by Maria Sharapova

Surely that must sting? “If those opinions were based on factual information, I’d go, OK, that’s fair,” she says. “But I don’t react when they’re not.”

But those facts are open to interpretation. Yes, the court of arbitration ruled that she did not take meldonium to boost performance. But others, including her own professional body, the International Tennis Federation (ITF), wanted to know why she took a drug that was not licensed in the US, and why she took it over a period of 10 years (instead of the recommended four to six weeks).

Has the ban changed her attitude to legal drugs and supplements? I mention the ITF tribunal finding that Skalny had prescribed her 30 substances. Surely she wouldn’t do that now, in the hope of marginally boosting her performance or stamina? She bristles. “It’s never about making me better or fitter, or any of that. It’s about staying healthy. And I’ve never taken 30, that’s for sure.” Yes, she says, she got disenchanted with that regime, but she’s never been one for regrets. “I’m not somebody who looks back and says, what if? That wouldn’t do anything. That’s a waste of time.”

It’s amazing, I say, that you can be so pragmatic. So many people would have gone under and given up. Only now, when I suggest that she took the ban with a pinch of salt, does her emotion begin to surface. “Well, let’s not say I was Happy Gilmore here,” she says. “D’you know the book Man’s Search For Meaning? It’s a great book about Auschwitz, written by a survivor, Viktor Frankl. I’ve read that book over and over. One of the greatest passages says that, when you put gas in a chamber, it doesn’t matter how small or big the chamber is, it will be filled with gas. Frankl said that when you think of unhappiness, the same is true: it spreads through all parts of your life. It’s not like, ‘Oh, now I’m just a little bit sad.’ When something like that happens, you’re faced with this reality of: I might not play for a really long time. It’s uncertain, it’s sad, there are so many emotions, and I was filled with them.” She gulps, and comes to a stop. For a second, she looks almost vulnerable. “No. I was not sitting there doing cartwheels.”

Maria Sharapova on the day she discovered she had failed a drug test: exclusive extract

I was imagining my retirement in the winter of 2015. I’d play through the winter and spring, appear at the Olympics in Rio, then begin my last professional season, with my book published just before the 2017 US Open. I’d tell my story and say goodbye. I remember talking about my 30th birthday party. I was full of plans. And you know how the saying goes: man plans, God laughs.

The 2016 season began at the Australian Open. Serena Williams beat me in the quarter-finals. It felt like a decent start to my 12th pro season. But, as sometimes happens in nightmares, what felt like the beginning turned out to be the end.

A few weeks later, when I was back in LA, training, I got a funny-looking email. It was from the International Tennis Federation. As I read, my heart started to pound. It said the urine sample I had given in Australia had come back positive. In other words, and I had to read this again and again to make sure I was not hallucinating, I had failed the drug test. How? What the hell could it be? I took nothing new, nothing that was not legal and prescribed by a doctor. It was called meldonium. OK, obviously this was a mistake. Who had ever heard of that? I Googled it, just to make sure.

Then I understood. I knew meldonium as Mildronate, the brand name. It was a supplement I’d been taking for 10 years. It’s an over-the-counter supplement in Russia, so common that you don’t think of it as a drug, let alone a performance-enhancing one. I’d first been told to take it when I was 18 and getting sick a lot; I had an issue with irregular heartbeats. For seven years, I had written confirmation that all the supplements I was taking, including Mildronate, were permissible.

As of January 2016, meldonium was included in a catalogue of banned substances that the ITF sent out to players. It was viewable by clicking through a series of links in an email. I never followed those links, and didn’t ask any of my team to. That was my mistake. But the ITF didn’t draw any attention to the fact that they were suddenly banning a supplement that was being legally used by millions of people. That was their mistake.

I felt trapped, tricked, but I figured all I had to do was explain myself. Meldonium had been banned for four weeks. At worst, I had inadvertently been in violation of the ban for less than 28 days. But I soon realised I was running into a brick wall. If I failed to win my case, I could be banned for up to four years. It would be the end of my career.

The news had not yet hit the press. I stayed strong on the outside, but on the inside every cell of me was crying. Then I asked myself, “Why not go out and explain to the world exactly what happened? Everyone will understand.”

I called a press conference less than a week later. I had told no one but my parents, my coach and my agent, Max. I wanted to be the one to tell it, in my own time, in my own way. I called a friend who is a hairstylist and asked him to come over with his gear. When I explained what was going on, he said, “You mean, all this time, we could have been doing really great drugs, and this is what you chose?”

It was the first real laugh I’d had in days. I could not tell marijuana from cocaine. That’s what made the whole thing so ironic. The people who really do the drugs, my guess is, they know how to protect themselves, so they don’t get caught.

Suddenly, no matter who I looked at, I found myself thinking, 'Do they think I’m a cheater?'

There were maybe 50 reporters at the press conference. There was speculation that I’d called everyone together to announce my retirement. I felt like I was dressed for a funeral, as I tried to explain what had happened. I felt so relieved exiting that room. I wanted my friends and fans and even my enemies to know, because I believed they would understand. I was wrong: some people came to my defence, but the newspapers really went after me, called me a cheater and a liar.

The firestorm that followed was the worst kind of mindfuck. Suddenly, no matter who I looked at, I found myself thinking, “Do they think I’m a cheater?” For the first time in my life, I was worried what people thought of me.

A few hours after the press conference, I sat in the kitchen talking to my mother. My phone rang. It was Max, who had just got off the phone with Nike. He said, “It was not a good conversation.” Two hours later, Nike put out a statement, and it was brutal. They were suspending me.

I was eating a rice pilaf my mom had made for me (when my mom can’t decide what to do, she makes pilaf). My phone started to buzz. It was a text from my old coach and friend Michael Joyce. I clicked on it, expecting support, but it was immediately clear this message was not meant for me. It was just one line – something like, “Can you believe Nike did that to her?” – but it cut to the quick. I suddenly had a sense of people I had known all my life, speaking about me behind my back. I ran upstairs to my room, sobbing. For the next two weeks, my mother didn’t let me go to sleep alone.

The morning after that was the hinge moment. Either you curl up in a ball, or you get up and carry on. I’d signed up for an 8.30am spinning class. My body felt heavier than it had ever been, even though I’d been losing weight; but something told me I had to go or I’d never get out of bed again.

At the studio, everyone was staring, or maybe that was just in my mind. I got on a bike, put my head down and made myself pedal. I cried through the entire class, but I did what I had to do. From that moment, I knew it was going to be awful and unfair, but that I’d get through it.

• This is an edited extract from Unstoppable, by Maria Sharapova, published next week by Penguin at £20. To order a copy for £17, go to guardianbookshop.com or call 0330 333 6846.

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