He may have illustrated a propensity to live dangerously and survive in the second round against Nigel Bond, coming back from 12-8 down to win 17-14, but yesterday former world champion Ken Doherty's powers of regeneration were never offered a chance against the aggressive potting ability of Welshman Mark Williams.

Doherty sat out a great deal of yesterday's World Championship quarter-final in the Crucible and at one stage it looked as though the former winner would ignominiously depart after only two of the scheduled three sessions. But character and tenacity prevailed and following a bleak 7-1 battering in the first session, Doherty doggedly fought back to take the score to 11-5 for today's final encounter.

Last year in the semi-finals Doherty showed himself to be the better all round player in beating the world number five 17-14 but the swashbuckling form of Williams coming into this year's tournament was nothing if not eye-catching.

Having won the Irish and Welsh Opens as well as the Thailand Masters during the past four months, the 23-year-old from Ebbw Vale declared after the second round:

"I am never going to come here in a better frame of mind than I am in at this time. My form can hardly improve all that much on what I have achieved this season."

And so he proved. Where Doherty was hesitant and lacked the ability to build sizeable breaks, particularly in the early stages, Williams was positively explosive and given any opportunity dominated the table.

The "Red Eye" start at 10.00 a.m. was particularly cruel to Doherty, who was skinned by his opponent and although the Irishman won the first frame from the modest platform of a 42 break, it was the highest score he could build in the entire session.

In the eighth frame the 1997 champion might have left the difficult morning behind him with a positive thought. He was 34-9 up, on the table and trailing 6-1.

But a kick on a simple red to a corner pocket let Williams in to build a break of 82 and terminate the session 7-1 rather than the possible 6-2.

Although the evening was a lot kinder, Doherty continued to struggle. Williams moved from 7-1 to 9-2 with the Dubliner scrambling to hold himself in the tournament.

Experience again told and without approaching the levels which won him the tournament two seasons ago, Doherty dug in to claim the next three frames in succession for 9-5 before Williams polished off the final two to hold onto his overwhelming dominance.

Doherty needs eight frames to secure a semi-final place today and Williams only two. Bearing in mind the Irishman built only two 50 plus breaks in total compared to Williams' five, including a 109, three 70 plus and an 80 plus score, today will be indeed be tough for the number four seed.

Earlier both reigning champion John Higgins and six times winner Stephen Hendry turned up the heat against Stephen Lee and Matthew Stevens. Hendry, making a comeback after one of the most frustrating phases of his career, goes into today's second session leading Stevens 6-2 while Higgins needs only five more frames to ensure his place in the semi-final. The 23-year-old Scot rattled out seven plus 50 breaks including a 132 to demolish Lee 8-0.

Ronnie O'Sullivan also indicated that he is coming through the bout of depression that threatened is career. O'Sullivan, seeded third leads John Parrott 11-5, going into today's final sessions.

World Championship (at The Crucible Theatre, Sheffield) - Quarter-finals: J Higgins (Sco) leads S Lee (Eng) 8-0 (Frame scores, Higgins first: 108-23, 132-(132 break) 0, 71-47, 73-47, 129-0, 95-30, 91-0, 64-34). Match resumes today. S Hendry (Sco) leads M Stevens (Wal) 6-2 (Frame scores, Hendry first: 7159, 75-4, 72-39, 65-64, 109 (109 break)-0, 0-63, 6-106 (100 break), 83-11). Match resumes today. R O'Sullivan (Eng) leads J Parrott (Eng) 11-5 (Frame scores, O'Sullivan first: 75-23, 70-4, 57-73, 76-74, 88-12, 68-58, 86-0, 89-2, 125 (120 break)-1, 0-79 (105 break), 77-18, 28-68, 0-105, 83-1). Match resumes at 10.00 a.m. this morning. M Williams (Wal) leads K Doherty (Irl) 11-5. Frame scores (Williams first): 43-81 76-23 77-37 78-32 56-5 80-23 78-4 91-34 74-56 50-57 54-26 58-66 9-70 31-87 109 (109 break)-0 64-45. Match resumes 2.30 p.m. today.