Ronnie O'Sullivan's campaign for a third world championship title ended last night when the bookmakers' favourite finally succumbed 13-9 to John Higgins after fighting intensely to stage a comeback from six frames behind.

The bulk of the damage was inflicted in the morning session as O'Sullivan, every department of his game malfunctioning, descended from 4-4 to an 11-5 deficit. Higgins, the 1998 champion, crucially stole two frames, the 14th and 16th, on the black from well adrift but to his credit O'Sullivan, a player who has often accepted his perceived fate too early, rallied determinedly last night.

Earlier, Shaun Murphy had produced the greatest quarter-final fightback in the 30 years that this theatre has staged the world championship by recovering from five down with six to play to beat Matthew Stevens 13-12. "I'd seen what had happened to Matthew and of course it was on my mind," said Higgins, who did not pot a ball as O'Sullivan swiftly rallied from 12-7 to only 12-9 in arrears. It was therefore with immense relief that Higgins controlled the 22nd frame to set up an all-Scottish semi-final against Stephen Maguire, who accounted for Anthony Hamilton 13-7.

"It's disappointing not to still be a part of the championship but at least I've found a bit of alignment towards the end," said O'Sullivan, who has not won a world- ranking event since the Irish Masters of March 2005. "Overall my technique let me down and I never felt as though I could completely keep John out."

Murphy, the 2005 champion, overcame Stevens after a final session of 3hr 40min during which the tension undermined fluency but engrossingly enhanced drama. "I had the game won at 11-5," said Stevens. "I missed a few chances. I should have won 13-7 when I was clearing up the colours but I just couldn't get over the line. I felt all right but the tension built up."

Murphy had resumed yesterday "never seriously believing I could win" but, as he noted Stevens slowly succumbing to "clinchers disease", he remembered Ken Doherty's extraordinary 17-16 semi-final victory over Paul Hunter in 2003 from 15-9 down and a few occasions when Stevens himself had failed to clinch a winning position.

The only cloud on Murphy's horizon is his rift with his father, Tony, previously the driving force in his career, with whom he has not spoken for 18 months. "He said a lot of stuff which just wasn't acceptable. He owes me an apology and unless he rings me to say sorry I don't know when we'll speak," said the 24-year-old. "I just had to stick up for myself."

As for Stevens, the promise of redemption after a disappointing season has ended in relegation from the elite top 16. He has reached two finals here, losing 18-16 in 2000 to his fellow Welshman Mark Williams from 13-7 ahead and two years ago to Murphy, 18-16, having led 10-6 after the first day's play.

Maguire made breaks of 96, 137 and 108 in the four frames he needed yesterday to give him a maiden semi-final appearance here. Hamilton did not pot a ball.

Murphy's semi-final opponent will be Mark Selby, who beat Allister Carter 13-12 after 9hr 10min play in a midnight finish. A crumb of consolation was that Carter's 144 break became the front runner for the 10,000 pounds highest break prize.