First things first: John McEnroe knows Serena Williams is great.

McEnroe, a tennis legend in his own right, has said that Williams, winner of 23 Grand Slam titles, is arguably the greatest athlete of the last 100 years . In 2012, he said, Youre watching, to me, the greatest player to ever play the game .

Which begs the question: Why is it that he, or anyone else, feels so compelled to try and belittle Williams legacy by comparing her to mens tennis players?

McEnroe landed himself back in the headlines over the weekend when he said Williams couldnt match up with male tennis pros during an interview with Lulu Garcia-Navarro , host of NPRs Weekend Edition Sunday.

While asking about McEnroes latest memoir , Garcia-Navarro noted, You say she [Williams] is the best female player in the world in the book.

Best female player ever no question, McEnroe said.

To that, Garcia-Navarro asked, Some wouldnt qualify it, some would say shes the best player in the world. Why qualify it?

You mean, the best player in the world, period? McEnroe responded.

Yeah, the best tennis player in the world. You know, why say female player? she asked.

His response: Well because if she was in, if she played the mens circuit, shed be, like, 700 in the world.