McEnroe sounds off on his chances against Serena

Decked out in a Kings of Leon T-shirt, John McEnroe appeared on "Brigitte Quinn’s 22 Minutes With..." to promote the January 7 PowerShares QQQ Cup at the Barclays Center in New York.

"It allows old people like myself the chance to think I could possibly beat a James Blake or an Andy Roddick or even Jim Courier for that matter," McEnroe said, adding he thinks Roddick could still be in the Top 20 today.

Will fans be seeing some of the famously irritable McEnroe from the 1980s?

"I could be playing the best set of tennis that I’ve played in 5 years, but if I don’t yell, 'You cannot be serious' or something along those lines... people feel like they’re not getting their moneys worth," he said. "But if I do do that, they’re like see you later. It’s sad in a way, but it’s also cool in a way.”

Donald Trump came up in the 22 minute chat, of course, and McEnroe called him the "Trumpster" before tying the president-elect into his answer about whether or not he thinks he can really beat Serena Williams (a topic that came up when he was on Jimmy Kimmel Live last year).

"Recently, as I’ve gotten older, I’ve become somewhat concerned about my ability to beat Serena, more so than in the past where I didn't have a concern," the 57-year-old said, adding that his four daughters think he would lose.

Trump, or the "Trumpster" apparently tried to coordinate a match between McEnroe and either Williams sister back in 1999 as a promotion attempt.

"It wouldn’t be that shocking if I did beat [Serena], right?" McEnroe said. "I mean, if he’s going to be president for God’s sake, it’s not that much of a stretch to think maybe I could beat Serena Williams, or possibly lose to her."

If nothing else, this interview shows that life in the spotlight, especially for McEnroe, continues long after pro tennis.