NICK Kyrgios could be in trouble again but this time he is pleading innocence.

Returning to the scene of his infamous tanking last year that led to a ban from the world tour, Kyrgios was involved in yet another walkoff at the Shanghai Masters.

TV footage and audio caught the Australian bad boy telling his courtside box he'd quit after the first set in an apparent protest over the decisions of chair umpire Fergus Murphy.

But Kyrgios claimed he was both injured and ill.

"Guys, I want to apologise to the fans in Shanghai and those that watched around the world on TV today," he said in a statement after walking off after losing the first set 7-5 in a tiebreaker against American Steve Johnson.

"I've been battling a stomach bug for 24 hours and I tried to be ready but I was really struggling on the court today which I think was pretty evident from the first point.

"My shoulder started to hurt in the practice today which didn't help either and once I lost the first set i was just not strong enough to continue because I have not eaten much in the past 24 hours.

"I'm hoping to be Okay for the doubles and will make a decision tomorrow morning, hopefully off a good night's sleep which I didn't get last night."

News Corp Australia

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