Roger Federer, Rafael Nadal, and Novak Djokovic have dominated men's singles tennis for two decades, raking in vast fortunes from sponsorships and prize money in the process.
The trio rank among the wealthiest sportsmen in the world, but the family wealth of a current top 10 player eclipses all their many millions combined.
Jessica Pegula, 30, is one of the biggest names in tennis, rising at one stage to become the second-highest ranked American woman behind Coco Gauff.
A Grand Slam title has proved elusive for Pegula, who has made it to the last eight of six consecutive Slams without progressing further, but she has won six singles titles and seven doubles titles on the WTA Tour, as well as three WTA 1000 titles in singles and two in doubles.
But while she's made plenty of money from the game, she stands to be worth a truly staggering sum one day thanks to her multi-billionaire parents.
Pegula is reportedly poised to be one of the inheritors of her father Terry, who has built a colossal sports empire in the US and owns the Buffalo Bills in the NFL and the Buffalo Sabres in the NHL with Jessica's mum, Kim.
Her father made his fortune in the oil and gas sectors and boasts an incredible net worth of around £5.7billion, according to Forbes.
The family's impressive wealth technically makes Pegula far richer than icons of the men's game, Roger Federer, Rafael Nadal and Novak Djokovic, whose fortunes are estimated to be less than a billion between them.
According to Celebrity Net Worth, Federer has racked up a reported fortune of $550million (£433.2m) through career earnings and endorsement opportunities, while Nadal is estimated to be worth $220million (£173.3m) and Djokovic at $240million (£188.9m).
Pegula has faced unfair accusations that her failure to reach Slam finals in the elite sport is down to her having a comfortable background, with a headline last summer suggesting she was missing a "dynamic" that her parents' "billions can't buy".
But in a recent interview with MailOnline, she pointed out that the Pegulas didn't become extremely wealthy until she was a teenager.
"People jump to these conclusions that are so over the top," she said. "I grew up pretty normal, and a lot of that [her family becoming billionaires] didn't happen to me until I was already older and playing.
"My goal since I was six or seven was to be number one in the world. So that was before a lot of this other stuff happened. I mean, before that, I was just a normal kid growing up in Pittsburgh, Pennsylvania, taking lessons after school.
"So I think that's just the kind of difference that maybe the casual fan kind of doesn't grasp as well," she added.