The combustible 21-year-old was booed off court and accused of giving up as he crashed out in the second round in a stormy five-set defeat to Italian Andreas Seppi on Wednesday, despite winning the first two sets.

John McEnroe labelled Kyrgios as “mentally (ranked) about 200 in the world” and giving the sport a “black eye”, while Rod Laver criticised his countryman’s antics.

The latest episode in the tempestuous tennis career of Kyrgios comes as he makes his return from a ban for “lack of best efforts”, commonly known as tanking, during a match in Shanghai. He has since been seeing a psychologist.

After he was penalised for throwing down his racquet in the third set, Kyrgios unravelled and started playing casually and lethargically, unnecessarily hitting a ‘tweener’ shot between his legs.

The tennis world remained incredulous Thursday over yet another of Kyrgios’s volcanic self-destructions from a winning position, but McEnroe was particularly damning.

“Even I’m at a loss for words. Overall I would call it a damn shame because I think he’s the most talented guy in the world (aged) 21 and under -— maybe even at 29 and under,” McEnroe said during television commentary on ESPN.

“He could be the best player in the world, but mentally he’s about 200 in the world, and I think at critical moments it showed.

“When he goes through those periods when he’s not competing, then it’s just a black eye for the sport. And it’s a black eye for him.”

– ‘Represent the game’ -Laver, the last player to complete the calendar-year Grand Slam, was more conciliatory but nonetheless took Kyrgios to task. 

“He’s got a lot of talent, yes, but behaviour is part of the game, part of any sport,” he told the Herald-Sun newspaper.

“And I think you’ve got to be able to represent the game you’re playing.”

Four-time Grand Slam champion Jim Courier said he was mystified by the mental state of the wayward star.

“It is amazing how it can go from so much fun for him to so much misery, when he wasn’t at peril at all,” Courier said during Channel 7 match commentary.

Davis Cup team-mate Bernard Tomic said he couldn’t believe how Kyrgios had lost the match against Seppi from two sets up.

“Regardless, he’s still an amazing player and he’s going to be huge in our sport,” Tomic said after winning his second-round match late Wednesday.

The media continues to be fascinated by the confounding Kyrgios, who polarises opinion among Australian sports fans.

Melbourne’s Herald-Sun headlined, “Kyr Factor Zero — Nick’s fine line between madness and genius”, while The Australian wrote, “Nick Kyrgios adds to shame file”.

As for Kyrgios himself, he said he was struggling with an injury he picked up playing basketball, and admitted he hadn’t trained hard enough pre-season.

“I’m disappointed,” he said. “I’m okay. Like, I’m all right. You know, the world keeps spinning. I lost one match.” DM