Judd Trump branded Ali Carter's behaviour "childish" after being dumped out of the Betfred.com World Championship.

Last year's runner-up frittered away a 12-9 lead to lose 13-12 in the second round, the 22-year-old title favourite beaten in a Crucible classic which reached its climax in a 46-minute deciding frame.

It meant the tournament lost one of its star attractions, not that Essex man Carter was concerned by that.

Carter was on the way back from the brink when he riled Trump in the 23rd frame by sarcastically applauding a shot from the Bristol youngster, who seemed to strike lucky when he tucked the white ball up in a snooker behind the brown and yellow after taking on and missing a long red.

"If he wants to do that, then it's up to him, but he's 30-odd years old and it's a bit childish," Trump said.

Carter, 32, insisted there was "no needle" between the pair, and Trump agreed, but said: "A lot of players enjoy me losing."

Carter claimed the win was one which would leave Trump scarred, and he was particularly pleased that the end was so painful, as the new Crucible darling threatened to win the decider from a point where he required four snookers.

Trump got three of them, but Carter then potted the colours he required to leave no way back.

Carter said: "In a way it makes it sweeter that I had to suffer for another 10 minutes and get out of snookers and play a bit more.

"Judd just pots them from everywhere but there's more to this game than potting them from everywhere.

"Now he can know what it feels like to have a nasty scar in your career and it's not easy to get over."

Trump reacted, saying: "I'm still a lot younger than him and have done a lot better, so let's just let the snooker do the talking."

Trump led 9-7 going into the final session, during which both men threatened to match Stephen Hendry's opening-day maximum break.

Trump's 147 attempt ended after 12 reds and blacks, Carter's after 11 reds and 10 blacks.

When it came to the crunch frame, Trump missed a red with the rest to present Carter with a match-winning chance in the decider. He made a telling 47 and victory was around the corner.

Carter, fighting an ongoing battle with Crohn's disease, an inflammatory bowel condition, had 2002 world champion Peter Ebdon supporting him and offering advice in the dressing room, which Trump said was "a bit strange".

Carter defended the move, saying: "It's all very well having these sports psychologists. But they don't know what it's like to be out there playing under pressure. Peter does and that's why I respect him."

Ronnie O'Sullivan was not to be denied a place in the last eight as he beat Mark Williams at the Crucible for the fourth time in seven years.

The three-time champion finished off Williams 13-6, and faces 2010 Crucible winner Neil Robertson next.

O'Sullivan said: "I think whoever wins this championship will have to beat Neil Robertson, and I've got to play him now.

"Neil's had a brilliant season, he's won the Masters. He's a big-time player and he's proved it on the big stage."

Two-time former runner-up Matthew Stevens joined Carter in the quarter-finals after beating Dartford's Barry Hawkins 13-11.

The 34-year-old will face Welsh compatriot Ryan Day in the last eight.

Stevens said: "Today was very tense, both of us kept missing the balls. it was tough but it's nice to get back in the quarter-final again."

A third Welsh player reached the quarter-finals tonight, with Shaun Murphy's first-round conqueror Jamie Jones, the world number 36, setting up a clash with Carter by defeating Widnes cueman Andrew Higginson 13-10.

Jones said: "I feel relief. I've played Ali before and I won it so hopefully that's a good omen."

Higginson said: "All credit goes to Jamie, but I'm disappointed. I've enjoyed my time here and you get a feel for the place."

All the quarter-finals begin tomorrow, with Stephen Hendry taking on Stephen Maguire in the morning session, at the same time as the tussle between Day and Stevens on the other table.