Tennis legend Roger Federer earned $64 million last year, Forbes estimates, making him the fourth highest-paid athlete in the world.
While the majority of his earnings were from off-court appearances and endorsements — $58 million — there's a lot to be made on court. The 18-time Grand Slam champion has won $104 million in prize money over his career.
If Federer collects an eighth Wimbledon title this year, his net worth will jump £2.2 million (about $2.8 million), according to Business Insider, the amount awarded to the 2017 singles champions.
But Federer and Tomas Berdych, who face each other in a semifinal match on Friday, won't be the only ones dealing with pressure on Wimbledon's Centre Court.
The ballkids, who are formed into teams of six and have been training for the tournament since February, are responsible for chasing down netted forehands, rolling balls quickly to the server's side of the court and repeatedly running towels to the players, among other miscellaneous tasks.
And the 250 Wimbledon ballkids, drawn from 800 applicants, do it voluntarily, a Wimbledon spokesperson tells CNBC.
At the upcoming US Open in New York City — the fourth and final Grand Slam tournament of the year — however, the ballkids will get paid about $11 an hour. Plus, if you continue to be a ballperson, you receive a raise every year, a US Open spokesperson tells CNBC.
While the wages are small, or nothing at all, the ballkids do receive a food stipend and get to keep their uniforms. Plus, without question, they get the best seats in the house while on the job.
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