It has taken Ken Doherty four years to rediscover the secret that made him the Republic of Ireland's only world snooker champion.

And having unearthed the winning formula again, Dubliner Doherty is determined to make the most of it.

The 31-year-old from Ranelagh became the first player to beat world title holder Ronnie O'Sullivan in a major event since last April when he scored a dramatic 5-4 Champions Cup victory at Brighton last night. Doherty has never progressed beyond the group stages of the competition in two previous attempts.

However, victory over Jimmy White tomorrow will guarantee his place in the semi-finals of the £200,000 event.

Indeed, Doherty's success over O'Sullivan, having trailed 3-1 at the interval, could already be good enough to make it third time lucky.

A winner of two ranking tournaments last season, the Welsh Open and Thailand Masters, he looks to have picked up where he left off.

"It's great to get that buzz back again," says Doherty, who starts the 2001-2002 campaign up at fourth on the world rankings. I've never been one to throw in the towel. But there is a huge difference between me now and how I felt 18 months ago."

O'Sullivan, who last sampled defeat at the hands of Mark Davis in the Regal Scottish Open last April, meets Peter Ebdon tomorrow needing to win to make the last four.

Ebdon can give himself chance of making progress by inflicting yet another Champions Cup defeat on White this afternoon.

White lost to O'Sullivan in his opening game and also lost all three group matches 12 months ago, hardly showing the form that merits his selection as a wild card entry.

The second match of the day features the two unbeaten players in Group B - John Higgins and Paul Hunter.

Both have two games to play, including Higgins' clash with Stephen Hendry on Thursday that could leave the seven times world champion with a rare wooden spoon.

Hendry went down for the second time in two days yesterday, beaten 5-3 by world number one Mark Williams.