The Irishman spoke of his relief at qualifying for the quarter-finals.

``At one stage I didn't think, I was going to get through,'' he said. ``Being 10-6 behind going into the final session was not the sort of situation I wanted to be in. Nigel played excellently in the first couple of sessions and probably deserved to be 10-6 ahead, but I'm delighted to come through it all.''

The 1997 champion was especially pleased with the form he produced to overcome the number 13 seed. ``I think to produce a high standard of snooker when you have to and when the pressure is on is important,'' he said.

In the quarter-finals, Doherty will meet the winner of a match between Welshman Mark Williams and English qualifier Nick Walker, who finished a very tight opening session level at 4-4.

Much-fancied qualifier MatthewStevens, who beat seventh seed Peter Ebdon in the first round, continued forward with a 13-8 victory over flashy Maltese Tony Drago to reach the last eight for the second successive year.

Earlier, reigning champion John Higgins took just one frame to finish his match with Mark King, winning 13-4.

Ronnie O'Sullivan had too much talent for Steve Davis's conquerer Joe Perry, leading after the first session of their second round match 5-3, including a century break in the third frame.