Mark Allen cooked up a storm on the opening weekend of the World Championships by branding Cao Yupeng a cheat after crashing out to the Chinese qualifier last night.

The Northern Irishman's season has been shrouded in controversial outbursts, but moments after he had surprisingly lost his first-round match 10-7 to a player ranked 81 in the world, Allen made the most damning of allegations.

Trailing 5-4, the world No 11 watched on as Cao appeared to strike the white ball twice with his cue while potting a red. Referee Paul Collier did not call a foul and Cao played on to compile a break of 33 on his way to winning the frame.

"He was in among the balls and Paul Collier missed a blatant push (shot). It was quite obvious to me... anyone at home could probably see that.

"It seems to be a bit of a trait for the Chinese players because there have been a few instances in the past, of fouls and blatant cheating going on. It needs to be corrected. He's a good enough player and he doesn't have to do that. He looked at the referee as soon as he did it, as if to say, 'Are you not calling a foul here?'

"It's very, very sad the state of snooker if it has to go down to that, but it's not the first time. Marco Fu and Liang Wenbo have been known for it in the past, so maybe it's just the Chinese players."

Actually, neither Fu nor Liang has been found guilty of cheating.

Cao was hurt by the accusations. "I didn't realise I did anything wrong or touched the ball twice. If I thought that, I would have said," he said. "But if I don't think that after looking at it, I will be very angry and upset about what Mark Allen has said.

Allen's outburst was the latest in a six-month barrage of insults which have landed him with fines and trouble. He swore while accusing snooker supremo Barry Hearn of caring only about money, not the players, at the UK Championship in December.

He has yet to be sanctioned for disparaging remarks made about the Chinese city of Hainan, tweeting ‘dead cats' and that ‘the place stinks'.