Serena Williams has asked for "respect" after John McEnroe claimed she would be ranked 700th on the men's circuit.
McEnroe said Williams was the "best female player ever" but insisted the 23-times grand slam champion would be a long way behind the top men's players when asked if she was the best tennis player overall.
"If she played the men's circuit she'd be like 700 in the world," McEnroe told National Public Radio. "That doesn't mean I don't think Serena is an incredible player. I do.
"And on a given day, Serena could beat some players... But if she had to just play the circuit - the men's circuit - that would be an entirely different story."
Former world No 1 Williams, who has taken time off from the game to have a baby, reacted testily to McEnroe's comments on Twitter.
"Dear John, I adore and respect you but please please keep me out of your statements that are not factually based," she wrote.
"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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