Tennis star Roger Federer crowns Serena Williams as the Greatest Of All Time

Roger Federer believed Serena Williams should be crowned the overall GOAT of tennis. Photo / Getty Images

Considered by many as the greatest tennis player himself, Roger Federer said he believed his closest contemporary may be a legend on the women's side.

The Swiss professional tennis player, who is currently ranked world No. 2 in men's singles tennis, told the Wall Street Journal that he considered Serena Williams to be the tennis GOAT (Greatest Of All Time).

Holder of 23 Grand Slam titles, Williams recently returned to the court after giving birth to her first child Alexis Olympia.

Federer, born just seven weeks before Williams in 1981, said watching the world No. 1 return to the sport had been "fascinating".

Serena Williams recently returned to the court after giving birth to her first child. Photo / Getty Images

"It's been fascinating to watch. She had a totally different upbringing—I came up through Switzerland with the federation, she did it with her dad and her sister," Federer said.

"It's an amazing story unto itself—and then she became one of the greatest, if not the greatest tennis player of all time."

And after being asked to clarify whether he considered Williams the ultimate GOAT of tennis or just on the women's side, Federer confidently replied "overall".

"It's not fair to compare, actually," he said, "But we know [Serena] is all the way up there."

"I'm probably up there with somebody, somehow. Maybe there's a group, a best of five—and if you're in that group, you should be pleased and happy. Tennis is a funky sport when it comes to that stuff."