Former champion Ken Doherty was made to work harder than looked likely at one stage as he completed a 10-7 victory against Cheshire's Nick Dyson in the first round of the Embassy World Championship at the Crucible Theatre, Sheffield last night.

Doherty, who has won two ranking tournaments this season and took this title in 1997, was 6-1 up on Dyson but the world number 114 battled back and made the Dubliner put in overtime.

A break of 90 by Dyson closed the gap to 9-7 but Doherty wrapped up his success with a contribution of 116.

"Nick played really well and made some good breaks," said the world number seven. "I could have been 8-1 ahead but he produced a couple of great pots and I was still happy to be 6-3 in front.

"It's good to get a test like that early in the tournament because it gives you a kick up the backside and stops you from getting too casual.

"I certainly didn't take Nick for granted because qualifiers come here for their big day out and can raise their game."

While every seed to have completed his match so far has gone through to the second round, two who finish today are in danger of being the first to fall.

John Parrott, the 1991 champion, trails Dublin's Michael Judge 5-4 as they battle for the right to meet Doherty - but eighth-seed Alan McManus has considerably more to do against Northern Ireland's Patrick Wallace.

McManus, from Glasgow, has lost in the second round for the last seven years but has a massive task to even reach that stage this time as he starts the deciding session 8-1 behind.

Wallace made an impressive start on his debut at the Crucible and knocked in a 135 break to lead 3-0, stretching further away after the interval to put himself well on course for a surprise win.

Ronnie O'Sullivan refused to rule out quitting snooker this summer after reaching the second round. O'Sullivan soared into the last 16 with a 10-2 trouncing of Devon's Andy Hicks, but insisted this could be his last appearance on the sport's biggest stage.

O'Sullivan has long been an enigma but a second successive World Championship first-round exit was never on the cards against Hicks and many experts are tipping the world number four to take the title.

"I just want to do what I want to do," said O'Sullivan, who confirmed he will at least be back at the Crucible to play Dave Harold on Friday.

"But sometimes you must move on and do other things. Eric Cantona did it and I'm sure he's not sitting at home crying his eyes out."