John McEnroe said while 39th-ranked Nick Kyrgios appears not to care what other people think, the Australian might live to regret not playing to his full potential.
Few former players are perhaps better qualified to try and fathom the inner workings of volatile Australian Nick Kyrgios than the original "superbrat" John McEnroe but even the American great struggles to figure him out.
Kyrgios, 24, found himself in hot water again at Queen's Club this week where he ranted against umpires, line judges, photographers and even fans. He was given a $17,500 fine for several counts of unsportsmanlike conduct.
He even accused a line official of "rigging" his match and threatened to walk off during a first-round win over Spain's Roberto Carballes Baena before losing his cool again in a defeat by Canadian Felix Auger-Aliassime.
In amongst all the histrionics, Kyrgios lit up the event with some magical shot-making not even the likes of Roger Federer or Rafael Nadal could conjure. Which makes his habit of self-destruction all the more frustrating for those who still believe he can be a force.
McEnroe, the bane of officials' lives in the 1980s with his regular tantrums, at least balanced his behaviour with seven Grand Slam singles titles and long stints as world number one.
Yet McEnroe believes outside of Federer, Nadal and Novak Djokovic, Kyrgios elevates the game like few others.
"He brings an electricity to tennis. That's why everyone is trying to figure a way to work through this so he can get to a place where he can go out and feel free to compete and give the effort," Eurosport analyst McEnroe said in a recent interview.
Kyrios has admitted "tanking" or not trying in several matches throughout his chequered career and in Rome this year walked off court mid-match after hurling a chair in a match against Caspar Ruud.
Deep into the third set against Auger-Aliassime on Thursday he appeared to lose interest, barely running for serves and playing a succession of exhibition shots.
McEnroe said the lack of effort is more concerning than the outbursts. "That's the part that gnaws at the players. I don't care if he throws a chair on the court or does what he does," he said.
"The part that I have a problem with, and I am assuming 99 percent of the rest of the Tour do, is when you go out there and don't seem like you are giving an effort half of the time for whatever reason. I don't know why, I am not Sigmund Freud!"
McEnroe said while 39th-ranked Kyrgios appears not to care what other people think, the Australian might live to regret not playing to his full potential.
"We all think about that. No matter how well you do. Myself included. It would be hard to believe he wouldn't think that," McEnroe said. "He seems in certain ways not to care what people think. And in certain ways that can be empowering.
"Alienating yourself it takes some guts in a way to put yourself out there."
Kyrgios made headlines before the French Open when in a podcast he said world number one Djokovic's post-match celebrations made him cringe. He also made spiky comments about Nadal and said the French Open "sucked" before pulling out.
"He doesn't need to say what he said about Novak in this podcast," McEnroe said. "If you say Novak, he's too busy waving to the crowd, is that the best you can come up with?
"I mean come on! Doesn't he deserve it since he has won 15 Slams? He can do whatever the hell he wants."