Ken Doherty departed the World Championships yesterday reflecting on a season which has fallen short of his heightened expectations.

While the former world champion managed to briefly rattle the cage of fifth-seeded Mark Williams in the dying stages of his 139 defeat, the Irishman simply didn't have the surgical game this year to make up the ground he lost in the frustrating opening exchanges.

While Doherty's battling instincts caused some tense moments as he moved from 7-1 down to 11-5 before taking four frames in the final session, nothing seriously threatened William's steady progress towards a semi-final meeting today with John Higgins.

"I won the first frame and lost seven. Seven frames to one was a big deficit to recover from. It is very hard to come back into a match after that sort of session, and that's where I think it was lost," said Doherty.

While Williams was typically aggressive and a constant danger with his potting ability, Doherty also ruefully accepted his own game's failings, one none-the-less capable of earning him Stg£34,000 this week.

"I could have been a lot sharper," he said. "I wasn't firing on all cylinders in any of the sessions. My season hasn't been very good, I have to admit. You know, I'll have to reflect about it during the summer and put a few things right. Right now, I think the tournament's wide open and that's a good thing for snooker and the sponsors, but I don't think I'll be turning on the television when I go home."

Williams, who had come to the Crucible having won three ranking tournaments this season, acknowledged the match was totally in his hands.

"If it had gone to 12-10, then it would have been wide open. But I don't think Ken could have won it. It would have been me throwing it away. I've more experience this year. I know the racket now if someone comes charging back at me," said the 24-year-old.

Doherty provided three 50 plus breaks in the final six frames, including a 75, his highest of the match. Compared to a thin run of five plus 50 breaks over the previous 16 frames, the disparity in form was both glaring and ultimately devastating.

Also safely through to the semi-final is the demon-driven Ronnie O'Sullivan. The world number three's stylish 13-9 defeat of John Parrott drew a superlative tribute from the sixth seed.

"His standard was just awesome, and his scoring on the ball was pure class. He's much more focused this week, and he looks like he's up for it. He's in the zone," said Parrott.

Higgins and Stephen Hendry are on a collision course to meet in a first all-Scottish Championship final. The defending champion and six-time former title winner are kept apart in the semi-final draw.

But an all-tartan head-to-head between the world numbers one and two for a £230,000 first prize is a distinct possibility.

Higgins admitted: "That would cap my career."

The 23-year-old Wishaw star was speaking only minutes after completing his 13-6 triumph over world number nine Stephen Lee.

Higgins was only just beaten to the winning post by former practice partner Hendry, who overwhelmed Matthew Stevens of Wales 13-5.

Both rounded off superlative performances in the best possible fashion. Hendry made the 450th century break of his career in the penultimate frame of the game; Higgins qualified for a meeting with Williams by knocking in a break of exactly 100 to round off proceedings.

Hendry's reward is a best of 33 frames match with twice former semi-finalist O'Sullivan.

Semi-final order of play: 2.0 p.m.: J Higgins (Sco) v M Williams (Wales) eight frames to play. 7.0 p.m.: S Hendry (Sco) v R O'Sullivan (Eng) eight frames to play.

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