The world-class athlete volleys back at the retired pro on Twitter on Monday.
Even when Serena Williams is putting haters like John McEnroe in their place, she does it with class.
The celebrated tennis star, who is currently pregnant, fired back at the 58-year-old former tennis star after he said that, if Williams played on the men's circuit, she'd be ranked "like No. 700 in the world."
WATCH: Pregnant Serena Williams Slays on the Tennis Court With Baby Bump on Full Display
"Dear John, I adore and respect you but please please keep me out of your statements that are not factually based," Williams, 35, wrote in a series of tweets on Monday. "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."
Williams' remarks were in response to comments McEnroe made during an NPR interview on Sunday in which he said that, while Williams is widely considered the greatest woman to ever play tennis, she wouldn’t be able to compete against her male peers.
"That doesn't mean I don't think Serena is an incredible player. I do, but the reality of what would happen on a given day is Serena could beat some players, I believe, because she is so incredibly strong mentally," McEnroe shared. "But if she had to just play the circuit -- the men's circuit -- that would be an entirely different story."
WATCH: Pregnant Serena Williams Shares Advice Her Mom Gave Her About Being a Parent
McEnroe went on to say that he doesn't think there has ever been a female athlete who could be considered the best player in their sport.
"I just haven't seen it in any other sport, and I haven't seen it in tennis," he said. "I suppose anything's possible at some stage."
Williams, who is currently ranked No. 4 by the WTA, has 23 Grand Slam singles titles and 14 doubles titles. In January, she won the Australian Open while eight weeks pregnant. McEnroe, who retired for good in 2006, has won seven Grand Slam singles titles and nine doubles titles.
WATCH: Serena Williams Cradles Her Baby Bump in New Pics From French Getaway
Earlier this month, Williams shared a video of herself playing a practice match with her growing baby bump on full display and still dominating the court. Check out the video below to see more.
