Nick Kyrgios may not have all the answers in his rollercoaster career but he reckons John McEnroe might.
The seven-time grand slam champion lashed Kyrgios after his shocking second-round Australian Open collapse against Italian Andreas Seppi.
McEnroe called Kyrgios' apparent lack of effort mid-match as "black eye for the sport".
Up two set to love the Australian No.1 self-destructed to lose 1-6 6-7 (1-7) 6-4 6-1 10-8.
"You know my history and career and all - I'm someone who's emotional and goes too far at times and says the wrong things," McEnroe said during commentary for Eurosport.
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"What I don't understand, and don't accept, and can't accept is when he starts going into the tank and he stops trying and giving 100 per cent.
"When he goes through those periods where he's not competing, that's just a black eye for the sport and a black eye for him."
Kyrgios made light of McEnroe's criticism at his post-match press conference, saying his "body was sore".
The comments by American, however, got under the 21-year-old's skin.
When asked about whether he had a sharp pain in his knee, Kyrgios responded: "I don't know, mate. Ask Johnny Mac."
And whether he was consulting a sports psychologist in person in Melbourne or on the phone: "Johnny Mac will know, mate. Just talk to him. He knows everything."
McEnroe said Kyrgios could be the best in the world if he got his mental game together.
"I would call it a damn shame because I think he's the most talented guy in the world 21 and under - maybe even at 29 and under.
"He could be the best player in the world, but mentally he's number 200 in the world and I think at critical moments it showed."
