John McEnroe claims Serena Williams would not be able to compete at men’s level

John McEnroe has thrown the cat amongst the pigeons after claiming that Serena Williams would struggle to compete on the men’s circuit.

Speaking to US radio station NPR, the seven-time Grand Slam winner said that Williams, who has won an open-era record 23 Grand Slams, would be “700 in the world” if she competed amongst male players.

Dmitry Tursunov, ranked 701 in the world, dipped his oar in – saying he believes he could beat her.

Williams responded to McEnroe via 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."

The 35-year-old won her 23^rd Grand Slam title at the Australian Open in January, unaware that she was pregnant at the time.