Mark Allen bowed out of the World Championship and accused his surprise Crucible conqueror Cao Yupeng of failing to own up to a "blatant" push shot at a pivotal stage in the match.

Northern Irishman Allen, who lost 10-6 to the world number 81, said he was "disgusted" with the behaviour of his 21-year-old Chinese opponent, who was making his debut in the tournament.

Allen, 26, also criticised the sportsmanship of Chinese players in general - sure to go down badly in the nation where snooker is a boom sport, hosting many major tournaments.

Cao firmly denied any knowledge of today's incident, which Allen stated came with his opponent on a break of eight in the 10th frame and playing a red with awkward bridging.

The break later ended on 33 and Cao won the frame to extend his lead to 6-4.

Allen said at his post-match press conference: "I thought the big turning point in the match was at 5-4 when he was in the balls and Paul Collier, the referee, missed a blatant push.

"It was quite obvious to me and anyone who was watching at home would have been able to see it."

There is no rule covering the issue but players are expected to call fouls which are not spotted by referees.

Allen believes he was denied what should have been a chance to make a substantial break.

He added: "It seems to be a bit of a trait for the Chinese players because there've been 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?'.

"I looked at Paul and I looked at Michaela (Tabb) who was marking the match, and I spoke to (Terry) Griffiths at the interval. He was commentating on the match.

"I was pretty confident at the time it was a foul, and he (Griffiths) pretty much confirmed it to me at the interval.

"It's very, very sad the state of snooker if it has to be down to that, but it's not the first time.

"I'm disgusted that it happened. It shouldn't happen in professional sport."

Allen named two players from the Far East who he claimed had cheated in the past.

Cao picks up double his previous career winnings for knocking out the current World Open champion.

Cao was asked in his press conference if he remembered the incident, but replied through a translator: "No."

He said: "I was just focusing on playing. I didn't realise if I had fouled. If I fouled, I say sorry. If I didn't foul, and Mark said that, then I would feel very upset and angry."

A World Snooker spokesman confirmed the comments from Allen would be examined by the World Professional Billiards and Snooker Association.

A pair of classy centuries - 108 and 113 - steered Cao to a 9-5 lead.

Allen responded with 101 to close the gap, and looked to have made it 9-7 when he cleared from blue to black.

There was a wicked twist though. As Allen roared his delight at potting an apparent frame ball, he had not spotted the white heading to a top corner pocket, and when it dropped the victory was Cao's.

Allen has caused major controversy twice previously this season.

He was fiercely critical of World Snooker chairman Barry Hearn during the UK Championship in December, and then during the World Open in February he wrote on Twitter that the Chinese island of Hainan, which staged the event, was "horrendous" and the people were "ignorant".

He was fined for the Hearn outburst, and his Hainan comments are still being assessed.