Serena Williams' go-to guy: Hitting partner Big Sascha

Douglas Robson, USA TODAY Sports | USATODAY

When Serena Williams crashed out of last year's French Open — her first opening-round loss at a major in 47 appearances — she did not turn to her longtime physiotherapist, her agent, or even her parents.

As she departed the grounds, she told her entourage to take separate cars and then climbed into the backseat with her hitting partner, Aleksandar Bajin. There, a distraught Williams let the tears flow.

If the Williams family remains a famously close-knit clan, one outsider has become so essential Serena refers to him as kin.

"Outside of my parents, I think he's probably the most important person on the team," Williams says of Bajin, who goes by the nickname Sascha. "He's much more than a hitting partner. He's my older brother. He's family."

As top-ranked Williams kicks off her quest for a sixth title this week at the Sony Open in Key Biscayne, Fla., Bajin will be a crucial, and sometimes underappreciated, part of her campaign.

Bajin spoke with USA TODAY Sports about his six-year association with Williams — a time in which he has been arguably the most stable and important pillar during a tumultuous period of her career.

From blood clots and hematomas to reputation-marring meltdowns, Bajin has been at her side.

He also has been present for seven of the American's 15 majors, most among active players; her singles and doubles gold medals at last year's London Olympics; and her reascension to No. 1 last month at 31 — the oldest female to hold that slot in WTA history.

Bajin admits the highs and lows in such close proximity have blurred the traditional barriers between employer and employee.

"The line between friendship and employee is gone a long time ago," says Bajin, "which makes it sometimes very, very hard because then it gets personal."

But hearing the words Williams used to describe their sibling-like relationship, the 28-year-old's cheeks reddened. "It makes me blush," he says.

Like most hitting partners, Bajin once had professional ambitions. A Serb born and raised in Munich, he was a promising European junior and ranked as high as No. 1149 in 2007, but his career stalled and he struggled with his motivation when his father was killed in a car accident.

His relationship with Williams had an unlikely beginning.

Bajin was working for a tennis organization in Munich when Williams' former hitting partner, Jovan Savic, called him late one night and begged him to train with her while she was in town. Bajin was out partying and initially declined.

Savic called back an hour later and said he couldn't find anyone. Lubricated by alcohol, Bajin relented.

"Turned out pretty good," he says of their initial liaison shortly before the 2007 French Open.

In the musical chairs of hitting partners, Bajin's gig is a dream job. But it is much more than the title implies.

Bajin plays multiple roles — trainer, coach, errand boy, bodyguard, confidant and consigliere. He trains and stretches with Williams. He fetches food. He scouts opponents. He books courts and arranges for racket stringing. He mimics playing styles.

"I can do basically anything she wants me to but play with the left hand," he laughs.

Bajin is not kidding when he says anything.

Sensing Williams was tense as she prepared to take the court against fellow American Sloane Stephens at an event in Brisbane in January, Bajin decided to moonwalk past the camera focused on the two players. Williams cracked up.

"She walked on the court with a smile," Bajin says.

"He's a psycho guy. He's a funny guy. He's a nuts guy," Williams says. "We're a lot alike."

"I'm just trying to make Serena's life as easy as I can in every aspect," says Bajin, who tries to set an example for her in the gym and on the court. "If I have to make a fool out of myself I'm glad to do that in order to get her motivated."

It's no secret that Williams can fly off the handle, as she did in losses at the 2009 and 2010 U.S. Opens. She has a mean streak, a characteristic her father Richard publicly boasted about when his two youngest daughters were coming up the ranks.

But she has also pushed him to the edge of quitting on more than one occasion — once in the middle of a warm-up.

"There were moments where she was like really mean and like nasty," he said. "That gets tough."

He's learned that Williams simply needs to let off steam, but says in the end it pays off. Their relationship solidifies. Her success continues.

"I told her always like, Look, I'm the only man, let it out on me, whatever it is, I can take it," he says.

Their loyalties run deep. He has passed out drunk next to her in bed. She knows the most intimate details of his life.

"She knows more about me than my own mother," he smiles.

When Williams was sidelined for 11 months in 2010-11 from a series of illnesses and accidents, including a pulmonary embolism and surgery for a grapefruit-sized hematoma in her stomach, Bajin stayed with her for most of the year. He cracked jokes to lift her spirit, grocery shopped, and crooned Karaoke songs with her.

While he was grateful that Williams kept him on his full salary, he grew eager to play and was offered the chance to train with former top-5 player Jelena Dokic.

Williams was less enthusiastic.

"Over my dead body," he says she told him.

It's not for everyone, but Bajin loves his job.

With Williams as an entree, he travels far and wide; he attends concerts and A-list celebrity events; he earns a decent wage compared to most hitting partners.

For about three years, he lived in Williams' apartment and house in Los Angeles, but eventually found it stifling as the only man around. He now owns a place in Florida, though he sees it little.

There are other sacrifices, too.

Bajin rarely calls his own shots. He longest relationship in the last decade was six months. Bajin, the middle of three children, is slowly losing touch with his mother and two sisters, who live in Munich.

He visits Germany twice a year, hardly enough to watch his new niece grow up or his younger sister's boxing exploits or even to stay in close contact with his mother.

"That's the hardest part because I lose the relation to everything that's going on there," says Bajin, the middle child. "Every time I come home my mom looks 50 years older."

Bajin says he feels "like a tourist" in his hometown, which "actually hurts a little bit."

"But then, I love it so much that I really wouldn't change it for anything," he says of his globetrotting lifestyle.

Bajin knows there are plenty of players out there that can do his job tennis-wise. But none would be as telepathically attuned to Williams' mood and body language. He makes adjustments accordingly.

"We communicate without even words," he says. "If I see her walking out on the court, I know exactly what I have to do: if I have to be a little bit more demanding, if I just have to hold back, if I have to make her run."

Sometimes that includes small gentleman's gestures, such as holding the car door open.

"The feeling for the situation is way more important" than hitting balls, he adds. "And I think that's my biggest advantage, that I really figured it out quickly. Even little things."

Bajin calls his years with Williams a "fun" and "crazy ride."

Perhaps nothing illustrates the vital position he plays in Williams' personal and professional life than the aftermath of her shocking first-round upset to 111th-ranked Virginie Razzano in Paris last year.

As Williams cried about her loss, Bajin suddenly recalled that it was close to the anniversary of his father's death. He then joined with his own tears in the backseat of the tournament transportation van.

"The driver is probably thinking, 'What is going on in here?' " Bajin says.

Bajin says if he were to lose his job or if Williams retires he'll likely team up with another WTA pro.

"I think I wasn't born to be a player," he says. "I think I'm way better at this, especially for girls."

In the end it is Williams who is out there competing, yet Bajin takes pride in his work.

"I'm sure Serena wouldn't keep me around six years if I was just a funny guy," he says. "I do like feel great because we are all part of history. We are writing history."