Serena Williams has proven her strength, quickness and grit on the tennis court in her 23 Grand Slam wins. On Monday, she took that same intensity to Twitter.

The tennis star, often dubbed the “G.O.A.T: Greatest of All Time” for her dominance in tennis, responded in two simple tweets to the comments from John McEnroe that she would “be like 700 in the world” if she played against men.

The tweets came just over 36 hours after McEnroe’s interview went live on NPR.

McEnroe said in an NPR interview that he respected Williams’ talents and believed that she is the greatest female tennis player of all time. However, he then said that he does not consider her to be THE greatest of all time.

A part of the transcript is below:

NPR’s Lulu Garcia-Navarro: We’re talking about male players but there is of course wonderful female players. Let’s talk about Serena Williams. You say she is the best female player in the world in the book.

McEnroe: Best female player ever — no question.

Garcia-Navarro: Some wouldn’t qualify it, some would say she’s the best player in the world. Why qualify it?

McEnroe: Oh! Uh, she’s not, you mean, the best player in the world, period?

Garcia-Navarro: Yeah, the best tennis player in the world. You know, why say female player?

McEnroe: Well because if she was in, if she played the men’s circuit she’d be like 700 in the world.

Garcia-Navarro: You think so?

McEnroe: Yeah. 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 some situations where players would choke ’cause she’s been in it so many times, so many situations at Wimbledon, The U.S. Open, etc. But if she had to just play the circuit — the men’s circuit — that would be an entirely different story.

Williams, however, wasn’t going to let McEnroe’s comments go unanswered.

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