(CNN) -- Before she was even born, Micaela Bryan already had her own Twitter handle.
Now just over 18 months old, she has more than 12,000 online followers. Some of them are among the biggest names in sport, including Serena Williams and Novak Djokovic.
The top-ranked tennis duo have both had star billing on @micaelabryan -- and Djokovic is quite the regular guest. "Uncle Rafa" might have been the early inspiration, but his on-court rival "Uncle Nole" has made a serious play for her affection.
"Every time Novak sees her it's really funny, he'll say, 'Micaela, my little buddy, how are you doing?' and he'll go and give her a hug," her mom Michelle Bryan told CNN's Open Court.
"And if she doesn't give him what he wants, like a good response, he'll say, 'You've forgotten about me already.' "
But Micaela will never forget Djokovic. When she grows up she'll have a permanent record of her encounters with Serbia's favorite sporting son -- it's all documented on social media.
"My wife masterminded it," says Bob Bryan, one half of the most successful men's doubles partnership in tennis history.
"She got @micaelabryan before she was born and I didn't even know about it, and then we got this picture with Nadal in Miami when he was just walking through the corridor toward the locker room and he kneeled down and took a picture with her.
"He says as a joke, 'Let's put it on our Twitter account,' and we put it on and woke up the next day, she had something like 750 followers.
"So it was kind of born right then. We were like, 'Now she has all these fans we've got to keep them happy,' so we just kept getting pics with stars."
The biggest "get" so far is undoubtedly Roger Federer, the record-setting 17-time grand slam champion of the men's game, who was pinned down at the 2012 French Open.
"He's one of those guys, sometimes at tournaments you don't see him he's so busy," says Bob of the Swiss superstar, himself a father of two young girls.
"He doesn't stay at the player hotel ... you might catch him in the locker room. But we saw him hanging out at the French. He was so nice, he's like, 'Take one this way, let's try this one,' doing lots of little poses. Micaela loved him and that was a high-five moment for sure."
Bob and his twin brother Mike have had plenty of "high-five moments" on the court in the past year -- or, to be more accurate in their case, "chest-bumping moments."
By winning Wimbledon in July, they became the first doubles team to hold all four grand slams and the Olympic title at the same time -- and success in their home U.S. Open this weekend would create history as they would own all four majors in a calendar year.
Only one other partnership has achieved it -- Ken McGregor and Frank Sedgman in 1951 -- but the Australians did so before the advent of the professional Open era in 1969.
On Monday the identical twins needed to save two set points in the opening set in a 7-6 (9-7) 6-4 victory over the British pairing of Colin Fleming and Jonathan Marray.
Though doubles is considerably lower profile than singles competition, the 35-year-old brothers have both earned more than $10 million in tournament prize money on top of their endorsement deals.
And both are acutely aware that, to capitalize on their playing success, they need a strong online presence.
"When companies are deciding between two athletes, they'll pick the one that's got the most followers or is more active on social media. They're looking at players that give them that extra marketing pop," explains Bob.
"It's really important for the athletes to stay connected with the fans, they really appreciate it. It's good for promoting yourself and promoting your sport. I think companies now really understand and appreciate the value of an athlete who has a big social reach.
"In our contracts now -- clothing, shoes rackets -- it's all built in, the number of tweets we have to send, the number of times you have to post on Facebook."
Although he has nowhere near the online following of Nadal and Federer, who both have upward of 10 million followers on Facebook alone, Bob says he was one of the first regular tennis tweeters -- and now many players use it to communicate during the downtime of touring life.
"I had a birthday (in April) and Novak Djokovic wrote me a direct message on Twitter -- it's a way we stay connected. It's getting away from email and texts and going towards Twitter and Facebook.
"It's one of the big reasons why I decided to put my daughter on it -- it's just another way to stay active and be creative with it. I don't like to just post pictures of rackets, so if I meet someone cool, or go to an interesting place..."
Micaela, too, is getting to see the world. And she's being primed for a life in tennis -- already boasting a racket deal "after a long 16 months of negotiations" according to a post on her Twitter page in June.
"I played tennis my whole life so I would love for her to play tennis, because for me it was amazing," says mom Michelle, a lawyer who played the sport at college.
"I developed mentally, I think I benefited from it growing up, all my friends played tennis -- the culture is something I want her to experience as well. But ultimately it's up to her."
Micaela may still be getting to grips with her nascent tennis swing, but she's already a dab hand with technology -- though more often than not it ends up in her mouth.
"She's a genius with the iPhone, she loves it. She's got the swiping down," says Mike, as he retrieves his mobile from the baby before it receives a terminal dribbling .
"We love having her on the road. That's the only way Bob would do it. He wants to see her develop and grow up, and we've seen her first steps, we see her roll over for the first time. And I'm a good babysitter -- I ask for $100 and I'll do it."
Life on the tour can be a grind, but having a baby on board can alleviate some of the stress.
"She doesn't care if we win or lose, so it keeps things in perspective," says Bob.
"We lost a tough one in Monte Carlo and had seven match points. We wouldn't usually talk for a few days, but she comes running at us, gives us a hug and laughing, she doesn't care."
Micaela may soon have company on the circuit -- Michelle is pregnant again. And the brothers have no intention of quitting yet.
"We're still having fun, we're eager, we still have some goals left," says Mike.
Bob: "We're perfectionists, I still don't think we're playing our best tennis. There's stuff we can improve and you want to get to that level before you shut it down."