She is the GOAT! - Roger Federer crowns Serena Williams 'the greatest' after becoming a billionaire

Whenever the conversation turns to the greatest tennis player of all time, Roger Federer's name is almost always at the forefront – alongside Rafael Nadal and, of course, Novak Djokovic.

However, the Swiss star has now surprised everyone by revealing who he personally considers the GOAT.

Instead of himself, Nadal, or Novak Djokovic, Federer pointed to Serena Williams.

With 20 Grand Slam titles and a record eight Wimbledon trophies, Roger Federer has left an indelible mark on men's tennis.

However, he admits that he found the greatest inspiration and admiration in the American's career.

"It was fascinating to follow her journey. She had a completely different upbringing than I did – while I was coming up through the system in Switzerland, Serena Williams built everything thanks to her father and sister.

"That story alone is exceptional, and then she became one of the greatest, if not the greatest, female tennis player of all time," Federer told The Wall Street Journal.

He added that he doesn't just measure her significance within the women's game, but across the entire history of the sport.

"It's not easy to compare, but we all know Serena is at the very top. Maybe there's a circle of the five best ever, and if you're part of that group, you should be happy and proud. Tennis is a special sport in that regard," Federer concluded.

Roger Federer's legacy as a tennis titan has now been cemented with an equally impressive financial milestone.

Pulse Sports earlier reported the retired Swiss maestro has officially achieved billionaire status, making him only the second tennis player in history to do so.

While his on-court earnings of around $131 million are substantial, they are only a fraction of his total wealth.

The true drivers of his fortune are a series of shrewd business deals, most notably his strategic investment in the Swiss shoe and apparel brand, On.

His 3% stake in the company, acquired in 2019, has skyrocketed in value since its 2021 IPO, now estimated to be worth over $375 million.

This savvy move, combined with a portfolio of lucrative, long-term endorsement deals with brands like Rolex and Uniqlo, demonstrates his financial acumen rivals his on-court genius.

He joins a rare echelon of athlete billionaires, a list that includes sporting greats like Michael Jordan and Tiger Woods.

This achievement solidifies Federer’s standing not just as a sporting icon, but as a business mogul in his own right.

The first tennis player to reach this financial height was Romanian player Ion Tiriac, who amassed his wealth through business ventures after his playing career.