Snooker: O'Sullivan edges past Williams in duel of the dual champions

Ronnie O'Sullivan eventually overcame Mark Williams 13-11 in the quarter-final duel of the two-times champions in Sheffield last night to secure his place in today's semi-finals at the World Championship.

Their tension-drenched match, which ebbed and flowed as O'Sullivan let slip a 10-6 lead to allow Williams to level at 11-11 was a fitting end to a day of high drama, big breaks, stirring comebacks and tight finishes.

Peter Ebdon, the winner in 2002, will get the semi-finals under way today at 2pm against Marco Fu. Ebdon prevailed 13-7 against the reigning champion, Shaun Murphy, who threatened to storm back into genuine contention. Fu, the world No 25 from Hong Kong, beat Ken Doherty, the 1997 champion, 13-10.

The first man through to the semi-finals was Graeme Dott, whose 13-12 quarter-final win over the qualifier Neil Robertson set the tone for a roller-coaster day. Dott led 10-6 at the start of play and increased that to 12-8 before Robertson reeled off four frames in a row for 12-12. The decider went to the last two balls. As he celebrated, Dott knew he would face either Sullivan, the winner in 2001 and 2004, or Williams, successful in 2000 and 2003. The first session of Dott and O'Sullivan's semi, which is a rematch of the 2004 final, is this evening.

O'Sullivan started last night's concluding session against Williams with a 10-6 lead that was cut to 10-8 after two frames. Williams should have made it 10-9 but missed the final red when well ahead and O'Sullivan stole in for 11-8.

Williams took the next three, a frame-clinching break of 78 sandwiched between two error-strewn frames where he had the run of the balls. At 11-11, he made a break of 37 before an exchange of misses. O'Sullivan made a break of 90 for 12-11.

O'Sullivan faltered at 43 in the final frame, missing a black from the spot, but Williams could not capitalise and allowed his nemesis back in.

Murphy was in desperate need of a comeback when he resumed play against Ebdon with the score at 7-1 yesterday morning. But after a superb session of near flawless play from him and some excellent recovery by Ebdon under pressure, he closed the arrears to be 10-6 down before last night's deciding session.

Ebdon had opened the day with a break of 67 for 8-1. Murphy then hit a break of 77 for 8-2 and, with renewed confidence, his long-potting clicked into gear. A screamer of a red to the yellow pocket was the starter in a knock of 83 in the 12th frame. Ebdon hit a 62 for 9-4, but breaks of 83 and 113 kept Murphy in the chase. Ebdon took the last of the morning for 10-6, and won three of four in the evening.

Fu and Doherty started the day at eight apiece. Doherty went to 9-8 with a break of 74. Fu hit back with a 135 for 9-9, and looked certain to go ahead when he left Doherty needing three snookers in the next.

But Doherty got them all to edge ahead before Fu won four frames on the bounce to seal the victory.

Dott beat Robertson, a 24-year old Australian, after going 50 points ahead in the decider and then ceding 37 points. Robertson still needed a snooker on the pink, but when trying to lay it and drop in behind the black, he potted it. Game and match over.