IT'S A COVETED day off in the middle of a tournament that will last two weeks and require him to play more than 20 hours of tennis, and Novak Djokovic is jogging into the Paris heat for his third workout of the day. He has already finished a morning hit-around. He has already stretched, drunk his recovery fluids, visited with a trainer, received a massage, talked about strategy with his coach and performed his yoga. Now comes another 90-minute practice on the red clay of Roland Garros, where Djokovic has arrived in late May with a chance to become the first man in 43 years to win four straight grand slams.

He is accompanied on the practice court by a group he refers to, always, as the Team-middle-aged men in sunglasses and hats emblazoned with the Djokovic logo who stand on the baseline with their arms crossed, watching to make sure no moment is wasted during this third training session on an off-day. A fitness trainer monitors Djokovic's footwork. A physiotherapist gauges his breathing. A manager, working his BlackBerry, schedules another practice for later in the week. A hitting partner lobs topspin backhands to mimic the next day's opponent. His coach, Marian Vajda, placing a water bottle in the corner of the server's box, tosses Djokovic a ball and tells him to take aim at the target set up across the net.

"Hit it and we're done?" Djokovic asks.

"No," Vajda says. "First you hit it five times."

Djokovic tosses the ball into the air, serves and misses. Vajda feeds him another ball. He rolls it over in his hand and bounces it against the court seven times. Serve ... miss. Serve ... miss. The pattern repeats, the Serb trying to hit a ball 125 mph at a four-inch target 60 feet away and missing by mere inches. But inches determine points, and points determine matches, and matches determine careers. The Team starts to fidget on the baseline. Vajda tosses another ball. Djokovic kicks the clay off his shoes and shakes his head.

"Relax. You're doing great!" yells a fan, watching from the stands.

For the first time all practice, Djokovic turns away from the court and surveys the scene around him. A crowd of at least 500 has packed into four rows of bleachers, choosing to watch a practice instead of one of the 12 matches currently unfolding in this first week of the French Open. Teenagers are climbing up a camera tower for a better view, ushers are scurrying after them, and on an adjacent court, the chair umpire of an actual match has stopped play in the fourth set to ask the practice crowd to be quiet.

Djokovic turns back to the court and calls for another ball. "I can't ever relax," he says to the fan, smiling, his eyes focused on the target.



WHAT DOES IT take to become the best when your competition is already the best ever?

That's the question of sports in the 21st century, the age of superlatives, when the fittest athletes train harder than ever before, aided by the smartest tactics, the most money and the best equipment. Marathoners lower the world record every few years. Golfers launch drives so far as to render courses obsolete. Football players weigh more and move faster.

But no sport has advanced in the past decade like men's tennis, where a rivalry among three once-in-a-generation players has accelerated the game's evolution. First Roger Federer, then Rafael Nadal, now Djokovic -- progression in the form of a battle royal. "It could end up that these are the three best players of all time," says Chris Evert, who won 18 grand slams. They hit with enough topspin to swing as hard as they want. They defend well enough to retrieve shots that were once certain winners. Entering Wimbledon, they'd won 28 of the past 29 slams and along the way created a version of the game unrecognizable to those who once played it best. "My ass would get kicked so fast and so hard," says Ivan Lendl, the No. 1-ranked player through much of the 1980s.

"The level of play is mind-boggling," says John McEnroe, commentating for NBC during a recent match. "I'm still trying to figure out how these guys do it."

Here's how: In his rise to the top of his sport, Djokovic has turned himself into a case study of what it now requires to be No. 1. Every detail is crucial. Every angle is considered. Every moment a chance to gain an incremental edge.

His food is gluten-free. His drinks are a combination of half a dozen vitamins and minerals. His sleep sometimes comes in a hyperbaric chamber. His reading material is about body awareness and mindfulness. His stress is tested using a biofeedback device. His water is lukewarm during matches because cold fluid idles too long in the stomach. His free time is, in fact, "recovery time," arranged by a professional scheduler. His celebratory beer in the locker room after winning a tournament is just that -- a single beer, a reward meant to entice performance.

His team of trainers and coaches travels with him 11 months each year. They sign confidentiality agreements that forbid them from discussing details of their work, because secrets are powerful, and power feeds greatness.

"In our sport now, there can be no room for weakness," Djokovic says. "You look for small advantages. Every shot has to be a weapon."

NOT LONG AGO, even the very best players possessed only a few weapons. There were big serve-and-volleyers like Pete Sampras and Boris Becker, great returners like Andre Agassi, artful net players like McEnroe and relentless baseliners like Jimmy Connors and Bjorn Borg. Their games were defined by strengths but also by weaknesses. "It was, 'Can I take advantage of this guy's soft spot again and again?'" says Patrick McEnroe, who played professionally in the '80s and '90s before coaching the U.S. Davis Cup team. "Now with these guys, you can't find the soft spots, and sometimes they barely exist."

Almost every player in the ATP top 10 travels with a full-time fitness coach and a trainer. Everyone can serve ... and return ... and volley ... and chase down angled shots that look like clean winners ... and generate enough power while stretching for a ball on a dead sprint to send those shots back with heavy topspin. "It takes five winners to finish one point," says Janko Tipsarevic, the No. 8 player in the world entering Wimbledon and Djokovic's best friend on tour. "One point now seems like a full workout." Rallies stretch for 20 or more shots. Matches can take five hours. The modern professional tennis calendar lasts almost 11 months.



Tournaments test players for steroids and other banned substances, but within the rules, they continue to pursue a physical edge by experimenting with all else imaginable. Some players build ice baths in their homes or travel to tournaments with oxygen tents. Others consult regularly with sports psychologists and nutritionists. Others go through elaborate warmup routines with gigantic rubber bands.

"You've got to be like an iron man in the triathlon," says Brad Gilbert, a former top-10 player who later coached Agassi for eight years. "Your heart rate has to go up to the sky, come down in a second and then go right back up. And somehow you have to psychologically convince yourself to suffer like that for six hours."

Indeed, few professional sports are so unforgiving of mental weakness, and the best players persevere by finding unshakable faith in something. Federer believes in his own superiority -- in the simple fact that he's destined for greatness. When he set the all-time record for grand slam titles, in 2009, he walked onto the court at Wimbledon in a monogrammed jacket with gold trim and then changed after the match into another jacket imprinted with the number of majors he had won. He sometimes travels without a coach, because who could teach him? He never grunts when he plays, because doing so would convey effort. Instead, he sits during changeovers and stares contentedly at the crowd, smiling, like an office worker enjoying his unhurried lunch break. His practices are relatively short but methodical. After matches, he says things like, "I don't play doubles often, but when I do, I tend to win." Or "I have a great record against anybody right now, so it doesn't matter who I play in the final." He doesn't mean to sound cocky when he says these things so much as matter-of-fact. He is the greatest player ever. The fate of every match rests in his control, because if he performs well, he will win. This is what he believes.

Nadal believes in routine -- in an obsessive succession of actions before every point that drives opponents crazy and keeps him sane, because the routine has worked for him thousands of times and therefore will work again. He straightens his socks and pulls them up as high as they go. He adjusts his shirt and then his shorts. He cleans clay off the baseline with his feet, stomping the dirt like a bull pacing the ring. He bounces the ball exactly 11 times before he serves. He refuses to step on the lines while walking onto and off the court. He spends changeovers sifting anxiously through his tennis bag, jiggling his knees, making sure everything is in its place. His practice schedule is a daily six-hour marathon of warmups and cooldowns. Adhering to the routine clears his mind. It offers a certainty that tennis does not. "It means I am focused," he says.

And then there is Djokovic, a man who spent the first several years of his career defined not by fitness but by fruitlessness -- a spindly baseliner from war-torn Serbia who performed silly impressions of players and deferred most major career decisions to his uncle, Goran. He was always a flexible player, with a two-handed backhand that could turn defensive shots into winners, yet from 2007 to 2009, his ranking idled at No. 3. He looked drained whenever a match required four sets. He quit in the middle of four grand slam matches and requested to see the trainer more than any other player on tour. "Cramp, bird flu, anthrax, SARS, common cough and cold," said Andy Roddick, sarcastically guessing at Djokovic's latest ailment late in 2008. Federer was even more blunt. "I think he's a joke, you know, when it comes down to his injuries," he said.

IF DJOKOVIC struggling to find a foundation for belief, it came one afternoon in 2010 with a random phone call from a stranger who knew nothing about tennis.

That January, Dr. Igor Cetojevic and his wife were flipping through channels on their TV in Cyprus when they stumbled across coverage of the Australian Open. Djokovic was playing against big-serving Frenchman Jo-Wilfried Tsonga in the quarterfinals. Cetojevic, a Serbian soccer fan, knew nothing about the technical aspects of tennis and didn't consider himself a fan. But his wife liked the sport and Djokovic was his countryman, so he stopped for a few minutes to watch.

Djokovic battled Jo-Wilfried Tsonga -- and his own fitness -- at the 2010 Aussie Open. William West/AFP/Getty Images

Djokovic had played well in the first three sets, winning two of them, and appeared poised to close out the match. Then, early in the fourth set, his breathing became labored, and his pace slowed. He called for a trainer. He leaned against the net between points. Tsonga seized momentum and ran away with the match. The television commentators blamed asthma.

"This is not asthma," Cetojevic said as he watched.

Cetojevic had spent the prior 20 years practicing alternative theories of medicine -- acupuncture, biofeedback, Chinese holistic medicine and magnetotherapy -- and knew that asthma symptoms were usually at their worst in the morning. This match was being played at night, under ideal weather conditions, and Djokovic had performed without problem for the first three sets. Cetojevic suspected Djokovic's breathing issue resulted from an imbalance in his digestive system -- particularly an accumulation of toxins in his large intestine. From a couch in Cyprus, he made his diagnosis.

"I think I can help him," he told his wife.

He reached out to Djokovic through a series of mutual contacts, and they met for the first time that July at a Davis Cup match in Croatia. Cetojevic explained that he wanted to help Djokovic with the "physical, mental, emotional and spiritual." Djokovic agreed to an initial evaluation, and the doctor checked his pulse and recorded his eating habits. He connected the straps of a biofeedback device to Djokovic's wrists and forehead to measure stress, environmental toxins, brainwaves and food allergies. He told Djokovic his body was sensitive to gluten and dairy and suggested some basic dietary changes.

A few days later, Djokovic met again with Cetojevic. He was already feeling better, he said, and he wanted Cetojevic to join the Team. "I will follow your instructions," he told the doctor.

For the next year, Cetojevic traveled everywhere with Djokovic and advised him on everything. "He had no idea how to eat," Cetojevic explained, and so he told him. No more cookies or pizza, even if he had grown up grabbing a few slices each day from his family's pizza parlor in Serbia. No more watching TV or playing video games while eating, because it kept him from being "present with his food." No more heavy meals with big portions of meat; he would eat lightly cooked vegetables and rice instead. No more sugary snacks during matches when he could have natural fruit bars. He instructed Djokovic to bless his food and to start every day with herbal tea before eating gluten-free cereal with fresh berries and nuts. And just in case Djokovic was tempted to waver from the routine, Cetojevic often made the meals himself.

Already skinny, Djokovic began to lose weight. "Some people around him were alarmed," Cetojevic says, "but I encouraged them to be patient knowing that, in time, his body would start to function better."

Meanwhile, Cetojevic continued to help Djokovic with the mental parts of his game through daily exercises ranging from the traditional to the obscure: emotional counseling, color therapy, meditation, visualization. Cetojevic provided Djokovic with reading material, asking him to regularly read through The Four Agreements, a book by a New Age spiritualist about looking inward to attain happiness and peace. Cetojevic thought the book would resonate with Djokovic in his rivalries with Federer and Nadal. "He was focusing on their strength and power and losing his center," Cetojevic says. "I helped him focus on his inner strength."