Serena Williams has told John McEnroe to “keep me out of your statements that are not factually based” after he reopened a timeworn debate by saying she would “be like 700 in the world” if she played on the men’s tour. That would put Williams (career earnings: $84.4m) just behind Brazil’s Wilson Leite (career earnings: $74,000) in the men’s world rankings.

Williams, who is set to be out of action until next year after announcing in April she is expecting her first child, said on Twitter: “Dear John, I adore and respect you but please please keep me out of your statements that are not factually based. I’ve never played anyone ranked ‘there’ nor do I have time. Respect me and my privacy as I’m trying to have a baby. Good day sir”.

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McEnroe’s comments came during an NPR interview on Sunday to promote his memoir, But Seriously. “Perhaps [her ranking] would be a little higher, perhaps it’d be a little lower,” he said. “And on a given day Serena could beat some players. I believe because she’s so incredibly strong mentally that she could overcome some situations where players would choke because she’s been in it 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.”

Williams has won multiple grand slam titles – 23 in singles, 14 in women’s doubles, and two in mixed doubles – and McEnroe was at pains to emphasise the 35-year-old’s skills: “That doesn’t mean I don’t think Serena is an incredible player,” he said, before adding that she is the “best female player ever — no question”.

McEnroe did not rule out a female player being able to dominate the best men’s players. “Maybe at some point a women’s tennis player can be better than anybody,” he said. “I just haven’t seen it in any other sport, and I haven’t seen it in tennis. I suppose anything’s possible at some stage.”

Williams’s most recent major victory came at January’s Australian Open, the seventh time she has captured the singles title in Melbourne. In April she confirmed she is expecting a child with her fiance, the Reddit co-founder Alexis Ohanian, and will take a break from tennis. She later said she will return to the tour in 2018.

Play Video 0:44 John McEnroe: 'She would be like 700 in the world'

In 2015 McEnroe, who is now 58, said he believed he could still beat Williams. “My daughters are over there,” he said during an appearance on Jimmy Kimmel Live! “I think it’s mixed, they think I’d probably lose to Serena. I believe that I could still take her.” McEnroe won seven grand slam singles titles, including three victories at Wimbledon.



Russia’s Dmitry Tursunov, ranked No701 in the world, told the BBC: “It would be a similar argument to: who would run faster, the fastest woman or the fastest man? Tennis is becoming more and more a physical sport, so it’s going to be hard for a woman to beat the men.”

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Williams has spoken on the subject in the past. In 2013, the American said she would lose to the current world No1, Britain’s Andy Murray, in “five to six minutes”.

“For me, men’s tennis and women’s tennis are completely, almost, two separate sports,” Williams said. “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.”

Williams has, in fact, tested out McEnroe’s theory. At the 1998 Australian Open, she played Karsten Braasch, who was then ranked No203 in the world, in a friendly single-set match. Braasch beat Williams 6-1 and her sister Venus 6-2. “In the end I won, but neither myself, nor Venus or Serena took the game too seriously - we were just having a bit of fun,” he told the Observer in 2001.