Ronnie O'Sullivan, the title-holder, lost the closing seven frames, and his temper, in being beaten 9-5 by Joe Perry in a huge upset in the last 16 of the Maplin UK Championship at the Telford International Centre last night.

En route to establishing a 5-2 lead on Monday, O'Sullivan compiled three century breaks but, on the resumption, the wild inconsistency that has plagued him throughout his career again reared its head. Perry took advantage as O'Sullivan fell victim to frustration.

In the twelfth frame, trailing only 23-0 and with nine reds remaining, O'Sullivan conceded on missing a tricky pot. He angrily wiped his cue across the table, caught the white and stomped into the mid-session interval 7-5 in arrears.

O'Sullivan, fined £20,000 when he walked out of his best-of-17-frames quarter-final with Stephen Hendry in the 2006 UK Championship when only 4-1 down, will face disciplinary action from the sport's governing body, the World Professional Billiards and Snooker Association (WPBSA).

“This is just a little £250 fine and a letter through the post,” O'Sullivan, having returned to play what proved the last two frames against Perry, said. “I've had a few of those over the years. It's no big deal.

“I just got outplayed. It was as simple as that. I felt very cold, I couldn't make anything happen and you've got to give Joe credit for the way he performed. That's the story of my game for a while - good at times, not good at others. I'm just inconsistent and it's something I've got to live with.”

Even at 7-5, O'Sullivan's chances could not be dismissed but when he missed a mid-range red early in the thirteenth frame, Perry, a World Championship semi-finalist at the Crucible in May, compiled a 69 break to tighten his grip.

O'Sullivan, the UK champion on four occasions, had an opportunity to produce a potentially tide-turning clearance in the fourteenth frame but, with much of the intricate positional work already done, missed a routine black off its spot and Perry completed his first win in their five world-ranking event meetings.

“I could see that Ronnie was getting anxious and running out of patience but I knew I had to keep the pressure on him,” Perry, who plays Marco Fu, of Hong Kong, in the quarter-finals, said. “I was happy when he conceded that frame. Any gifts, especially at this time of year, are gratefully received.”

Ding Junhui constructed a 147 break but achieved nothing else of a positive nature in going out 9-4 to John Higgins. Break-building perfection arrived in the third frame as Ding, who recorded a maximum in the Masters at Wembley last year, became only the sixteenth player to score a 147 break and lose. His latest yielded a £25,000 bonus and the championship's £5,000 highest-break award.

However, the 67th maximum in professional competition, 44th in world-ranking tournaments and eighth in the UK Championship, was not a catalyst for Ding to control the match. He enjoyed no further success in the first session as Higgins, more measured and infinitely more determined, gradually pulled away to 7-1.

The silence of the WPBSA was deafening yesterday in the wake of irregular betting patterns surrounding the first-round match between Stephen Maguire and Jamie Burnett, fellow Scots and close friends.

Maguire won 9-3 after substantial correct score wagers were laid on that eventuality, causing numerous wary bookmakers to suspend betting, some as early as Friday. Burnett committed a series of errors in the closing two frames, including a slowly rolled final black in the twelfth frame that was grossly off target. Both players have denied any wrongdoing.

The bookmaking fraternity are up in arms and it was widely expected that the WPBSA would, at the very least, announce that an investigation has been launched. Instead, it said nothing.

The WPBSA even refused, despite repeated requests, to confirm or deny that an investigation would take place. Sir Rodney Walker, the WPBSA chairman, declined to comment.

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