Not long after Padraig Harrington had for the second day in a row taken a stranglehold over an opponent, following up his humiliation of Nick Faldo by beating Darren Clarke by 5 and 4, came as good a reason as any as to why complacency should not be allowed to enter the psyche in his quest to become the first Irish winner of the Cisco World Matchplay Championship at Wentworth.

Sam Torrance, ranked a lowly 1,187th in the world, and who as European team captain has spent much of the past year worrying about the Ryder Cup rather than focusing on his own game, defeated world number five Vijay Singh. The Scot's win, which caught everyone by surprise, served as a timely reminder that matchplay has an intrigue all of its own.

While Harrington must get his head around the fact that, a day after beating one of his friends on tour, he must prepare to take on his coach's son in the semi-final, the manner of his win over Clarke provided further confirmation he has developed as a player of genuine stature.

"A world class player, now," was Torrance's malice-free observation of the Dubliner, and further evidence of his rise and rise in the world game came before yesterday's round when Harrington was confirmed as one of Tiger Woods's hand-picked participants in the confined 12-man field for the Williams World Challenge in Los Angeles in December. The minimum prize money there is $200,000.

Yesterday, however, for much of the morning, it was something of a slog. Some of Harrington's putting was, in his own words, "awful" but he still had a better time of it than Clarke, who had 33 putts - and missed five times from inside seven feet - in the opening 18 holes. At that stage, and despite two poor drives on the 17th and 18th, Harrington was two-up and a quick phone-call to his coach, Bob Torrance, between rounds solved his problem with the driver.

For Clarke, though, the misery continued. In pursuit, he watched three successive putts - on the second, third and fourth holes of his second round - all hit the cup but refused to drop. He must have known it would not be his day, especially when Harrington's five-iron approach finished just five feet from the hole and he rolled in the eagle putt.

"If there was a turning point, that was it," remarked Harrington later. "Even though it was only one more hole, it sounds a lot better than two-up . . . and it felt a lot better. Instead of hanging on, I started to think of winning more holes and that is what I did."

That eagle, in fact, started a streak that left Clarke floundering. Harrington reeled off five successive threes and moved from two-up to six-up and, almost before Clarke was aware of it, the match had slipped from his grasp. Even though he reduced the deficit with a six-foot birdie at the ninth and a 40-footer at the 11th, Clarke's time was running out and, typically, it ended on the greens when his four footer to keep the match alive performed a complete 360-degree trip around the cup but refused to drop.

Harrington's feat of covering the front nine holes in 30 strokes was matched by Torrance, who trailed Singh by two holes after 18 and found himself further adrift when losing the first of the afternoon round. Torrance brought the match back to all-square when winning the 10th - after Singh's tee-shot missed the green - but he had to wait until the 17th hole, the 35th of the match, before edging ahead with a birdie. With both players only parring the last hole, Torrance - in one of the great upsets of this championship - grabbed a place in the semi-final.

"I knew it would be a tough day before I started and it was a case of just plugging away. It is not as good as winning a golf tournament, and totally different from holing the winning Ryder Cup putt in 1985, but I'd rate it as the best singles win that I have had," said Torrance.

As a 48-year-old, and one who was only drafted into the championship at breakfast time last Monday morning, Torrance could be forgiven if he was emotionally and physically drained. He insisted, however, "there is plenty of fuel left in the tank".

Torrance's exploits over-shadowed a couple of other fine performances from Ian Woosnam and Lee Westwood. Woosnam was a 4 and 3 winner over Colin Montgomerie - "I'm a little surprised to be still around, although I have been playing well of late, " said Woosnam - while Westwood, without a win all year, showed his competitive instincts by overcoming a two-hole deficit after 18 holes to claim a one-hole win over the Dane. Westwood played the best golf of the day in the afternoon, shooting a round of 63.

Woosnam, who was due to be assistant captain to Torrance at The Belfry last month until the Ryder Cup was postponed for a year due to the terrorist attacks on the US, admitted to feeling tired before closing out his match with Montgomerie. His place here came about because top-ranked Americans decided not to travel . . . but Woosnam, even if he has been feeling each of his 44 years over the past few days, will relish the chance to take on Europe's number one of last season, especially having yesterday seen off the man who occupied that spot for the previous six years.