Ex-tennis great, John McEnroe has put a rather bold statement out to Serena Williams which is set to cause a bit of a stir.

McEnroe recently stated in his new book that Williams is the greatest female tennis player in recent history, but in an interview with NPR’s Lulu Garcia-Navarro has claimed that she would have a lot more to contend with if she was playing against some of the current male players.

Williams is fresh from winning this year's Australian Open, where she managed to overtake Steffi Graf with the top most Grand Slam singles titles during the 'Open' era, recording a stunning 23rd title.

Despite her fantastic record on the female stage, McEnroe is not convinced Williams would be able to come even close to emulating that success in the men's game.

"Well because if she was in, if she played the men's circuit she'd be like 700 in the world," claimed McEnroe.

"That doesn't mean I don't think Serena is an incredible player. I do, but the reality of what would happen would be I think something that perhaps it'd be a little higher, perhaps it'd be a little lower.

"And on a given day, Serena could beat some players. I believe because she's so incredibly strong mentally that she could overcome situations where players would choke 'cause she's been in so many times, so many situations at Wimbledon, The US Open etc.

"But if she had to just play the circuit, the men's circuit, that would be an entirely different story." 

Despite the controversial nature of McEnroe's comments, Serena has been similarly pessimistic about her chances in the past too.

When speaking about the prospect of facing Andy Murray in a charity match four years ago, Williams expressed her reluctance.

"For me, men's tennis and women's tennis are completely, almost, two separate sports," she said, as per USA Today.

"If I were to play Andy Murray, I would lose 6-0, 6-0 in five to six minutes, maybe 10 minutes."

"No, it's true. It's a completely different sport. The men are a lot faster and they serve harder, they hit harder, it's just a different game. I love to play women's tennis. I only want to play girls, because I don't want to be embarrassed."