In the past,homemade video. sex swing John McEnroe has heaped praise upon Serena Williams, previously saying she "greatest female player he's ever seen," but now he'd like the clarify his statements.

While on NPR, McEnroe talked about how no day goes by without him hearing someone repeat his famous outbursts ("You cannot be serious!"), and discussed his latest memoir But Seriously–but not before talking about the one person you must bring up in any tennis-related conversation: Serena Williams.

NPR's "Weekend Edition Sunday" host Lulu Garcia-Navarro asked the tennis legend why he chooses to qualify her greatness by specifying she's the "best female athlete ever." You can hear the exchange below, starting at the 6:20 mark.

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

"Well because if she was in, if she played the men's circuit she'd be like 700 in the world," he responded.

"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," he said.

"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," he continued.

Later in the conversation, he explained that one day, that could not be the case.

"Maybe at some point a women's tennis player can be better than anybody. I just haven't seen it in any other sport, and I haven't seen it in tennis. I suppose anything's possible at some stage."

To that, we have to say: you cannot be serious!