Rapid quarter-final victories brought Ronnie O'Sullivan, the world champion, and Paul Hunter, the Masters champion, together in this evening's semi-final of the Totesport Grand Prix at Preston Guild Hall. One punter won £3,000 for a £20 stake for betting on two whitewashes.

O'Sullivan swamped Mark Selby, 21, to whom he lost in the China Open two years ago, 5-0 in 71 minutes, making breaks of 135, 62, 135 and 76 in outscoring him 522-46.

"It all came together," said O'Sullivan. "My safety, break-building and thinking were good. It's as good as I've played in the tournament."

After an opening frame which could have gone either way Hunter was almost as dominant against James Wattana, appearing in his first ranking quarter-final for five years, whom he despatched 5-0 in 69 minutes with 64 and 93 as his highest runs.

"I didn't feel that I cued as well as I did against Steve Davis but James gave me quite a few chances," said the 26-year-old Yorkshireman.

Ian McCulloch, growing up in Preston, would sometimes sneak an afternoon off work to watch snooker at the Guild Hall, scarcely dreaming that he would one day beat players like Jimmy White, Stephen Hendry and, yesterday, the European Open champion Stephen Maguire 5-2 to reach this afternoon's semi-final.

"If I won a ranking tournament here, it would be like my world championship," said the 33-year-old, 12 years a professional but only in the last couple becoming a familiar face on television screens.

There is little margin for error in best-of-nines, one of the reasons that there have been so many surprises this week, and the players agreed that the key moment came as early as the second frame.

Maguire, having taken the first with an authoritative 80 break, lost position for the pink when apparently clearing up for 2-0.

McCulloch potted the pink to level and settled into commanding form to run through the next three frames with breaks of 81, 73 and 137. He missed two easy balls and lost the next frame to Maguire's 73 but bolted his concentration back into place for the 55, mostly blues, which left Maguire with the unlikely task of obtaining two snookers to save the match.

McCulloch's next opponent, this afternoon, will be a 29-year-old Dubliner, Michael Judge, who reached his first ranking semi-final in 12 years as a professional with a 5-1 win over Joe Perry.