John McEnroe has never been known for his humility. But even by his standards, his latest declaration is pushing it.

Appearing on Jimmy Kimmel Live, McEnroe discussed the current state of tennis, particularly Serena Williams, who's on the verge of a Grand Slam. When asked, McEnroe said that he believes he really could defeat the tennis star today.

“Fifteen years ago Donald Trump … made an offer which I felt like was not enough,” McEnroe said of a proposed exhibition match. “And I think he was humoring the two of us. And Serena, she’s got a lot to lose by losing to an old fart like myself. And I’ve got a lot to lose because if I lose to – God forbid – a woman, then I’m not allowed in any men’s locker room for the next 15 years or possibly the end of my life, so that’s part of why it’s intriguing.”

McEnroe, 56, still plays in some senior events but did detail later in the interview how he doubts he can keep up with many of today's tennis stars. Which makes his statement of being able to handle one of the best in the world massive even by his famed ego.