(CNN) -- She towers above him, but she can't do without him -- so much so they even email each other up to 75 times a day.
From the time they met 15 years ago, Maria Sharapova has been able to count on a man who has masterminded her rise to becoming the world's highest-paid female athlete.
"He knows everything that's going on. He knows where I'm going to be tomorrow, he knows where I am now," she told CNN's Open Court show.
"He" is Max Eisenbud, who first met the Russian when she was a 12-year-old tennis hopeful working with renowned coach Nick Bollettieri in Florida.
Then Eisenbud had a low-paying job liaising with young players' parents at the Bradenton academy that IMG bought off Bollettieri, but now he's Vice President of Tennis at the world's leading sports agency -- having made a fortune not only for Sharapova but also China's most bankable tennis star, Li Na, the No. 2 earner on Forbes' 2012 female athlete list.
"As an agent you just get lucky sometimes, and I'm just a really lucky guy," said the 41-year-old agent.
"I just really try not to mess it up!"
His lucky day came on July 3, 2004 when the 17-year-old Sharapova stunned Serena Williams -- and the tennis world -- in the Wimbledon final to win her first grand slam title.
With her model looks and youthful charm, blue-chip sponsors fell over themselves to get a piece of the action. Forbes magazine reported that Sharapova earned almost $28 million in the year up until June 2012 -- $22 million of that was from endorsements.
They might make something of an odd duo, with the glamorous Sharapova standing at 6 foot 2 inches and Eisenbud, a short, balding man from New Jersey, but as a business partnership they have the perfect synergy.
"We've just been very open and honest and real, and he's someone who says it like it is," said Sharapova, who like Eisenbud was born in April -- but 15 years apart.
"I think that's one of the greatest things that I appreciate in people, and he's done that from the very beginning. He understood the dynamic of me being the athlete, of working for me.
"Agents have much bigger jobs than just everyday life -- booking planes, looking into your agenda -- of course he's trying to make you money and make you big deals, but at the end of the day, he does everything for me.
"He has this old-fashioned calendar and just looks at every date. He knows my schedule, exactly when I'm flying to this tournament, when I'll be back, when we can fit this in.
"He knows my training hours so there are some things that I prioritize over others, and there are certainly some shoots creatively that I would like to do and he's like, 'We just don't have time for it', so I have to ax that out, but we usually agree on many things."
While Sharapova is comfortable on the red carpet and at celebrity parties, her manager is happier making deals.
"He's constantly looking at his BlackBerry ... if you need to get his attention, you should probably send him an email. That's the way I see our relationship," she said.
"He's very good at some things; others he's just absolutely hopeless at, like if you go to an event and you're on the red carpet, he has no idea what's going on.
"He's like 'Hey' and he's talking to all these people and you're like, 'OK, where am I going? Am I doing interviews? Or a step and repeat? What's going on?'
"That's not his forte. His thing is getting on the phone, getting deals done, getting the schedule together. All those business decisions, so there are things that I know I need to bring in other people for."
Eisenbud sees his role as a juggler of commitments.
"I think I'm more of a facilitator, an organizer. I know when to bring things to her because she's in the middle of a tournament, and when she needs to stay focused some more, so it's not distracting her tennis," he says.
"I think that's kind of my skill. We do probably anywhere between 30 and 75 emails a day between us, so sometimes we don't even need to talk on the phone. She just sets the vision and I'm just able to try to do my best to try and follow her vision."
From clothing and cosmetics to her latest foray -- a self-funded candy line -- Sharapova has a strong business strategy.
"If I didn't want to play tennis again, I'd have enough money to live for the rest of my life but I do respect the money that I've made because I didn't grow up having a lot of money," said Sharapova, whose parents fled their native Belarus soon after the 1986 Chernobyl nuclear accident, just before she was born.
Her father accompanied her to the United States in 1994, taking low-paying jobs before she enrolled at the $35,000-a-year IMG academy on a scholarship, aged nine.
"My family never had it, so I'm always very respectful for every single dollar that I make to this day. I really came from nothing," she said.
"I was living a normal, average, everyday life back in Russia and we had a dream and I had a talent and we moved to the U.S.
"Of course I'm so lucky and fortunate to have and earn great money but at the end of the day, we did earn it with my parents and their hard work and their sacrifices and all the hours on the court."
Eisenbud may work with other players -- he has a group of young hopefuls as well as Li -- but he says Sharapova will always be his focus.
He's been there from her early highs, to the lowest of the lows when it seemed a shoulder injury would end her career back in 2008.
"I've been with her so long, to see her smiling on the court, there's nothing better," he said, with Sharapova this year winning the Indian Wells title in March and last Sunday beating Li in the Stuttgart final to retain her title.
"It's pretty hard for me. I know too much information that other people don't. I know what's on the line, where we are with different things and what wins would mean, so I get a little nervous."
With Li also earning big deals, Eisenbud is akin to football's "super agents" such as Jorge Mendes, who works with Cristiano Ronaldo and Jose Mourinho.
"Rather than competing against one another, Sharapova and Na actually provide Eisenbud's business with much greater global coverage," British sports business expert Simon Chadwick told CNN.
"There is a degree of overlap in that they are both global tennis stars, whom the general public are aware of. This poses issues of clarity, focus and targeting for Eisenbud.
"However, as brands, they are significantly different propositions, which means that they are likely to appeal to different groups of people in different countries around the world."
Life after tennis
It was last year's French Open success that really crowned Sharapova's comeback, having been written off after a long struggle to rebuild her career following that shoulder operation.
"That was emotional, I definitely had a lot of tears," Eisenbud recalled.
"I was with her when she had the shoulder surgery, I was there when she woke up, I saw her first rehabs, I saw all the tough times, I heard all the journalists writing her off, Pam Shriver saying she'll never win a grand slam again, all the people just 'never never never.'
"If I'm seeing it I'm sure she's seeing it, so when she was able to win that -- get on her knees and win that French Open -- that was just a lot of, 'I told you so' and 'don't count me out.'
"Here's a great champion that had all the money in the world, all the glory, all the titles, but she wanted to come back and win, and it just says a lot about her."
But the injury did turn Sharapova's thoughts to life after tennis, and the resulting launch last year of her "Sugarpova" candy was her first independent business project.
"There's a lot of downtime on the tour and she uses it a lot," Eisenbud said. "She's involved in everything she does, she's not a silent owner -- she runs and drives everything that she's doing and I just try to implement it while she's on the court.
"Everything we've been doing now for the last couple of years has been thinking about life after tennis. We didn't want her career to end and then all of a sudden start thinking about it.
"I think Sugarpova will be a huge business for her after tennis. She'll be getting into a lot of different things -- cosmetics, fragrance, clothing -- so I think it's just the beginning right now for her."