With a mere 45 minutes for lunch, Padraig Harrington's first thoughts were not of food, but rather on how to fix a golf swing that was slowly dismantling. So it was that, two-up on Darren Clarke after the first 18 holes of their Cisco World Matchplay Championship quarter-final at Wentworth yesterday, the Dubliner - and his mobile phone - headed for the driving range instead of the restaurant.

The phone call was to his coach, Bob Torrance, whom he had assumed was watching the golf on television at home in Largs, in the west of Scotland. Upon speaking to Torrance, father of Sam, Harrington discovered he had actually been out playing golf himself on the local course but, fortunately, had been recording play on his video.

"I told him to rewind to my drives on the 17th and the 18th holes," said Harrington, selecting the two ugly hooks that had threatened to derail him. The result of the telephone conversation was an immediate assessment of what was wrong. "Quite simply, he told me that I was flat-footed. It happens when I get a little tired but it hadn't dawned on me that my feet were the problem. I just hadn't put two and two together," he added.

The quick fix worked, as Harrington - who had struggled with his drives late-on in his morning round and with much of his putting, despite claiming a two-holes advantage - totally dominated the play in his afternoon tussle with Clarke. He covered the front nine in a mere 30 strokes, including a run of five successive threes, and forged out a 5 and 4 win over his fellow-Irishman.

In today's semi-final, Harrington will meet Sam Torrance, a surprise but well-merited winner over Vijay Singh, while Ian Woosnam - conqueror of Colin Mongomerie - is scheduled to meet defending champion Lee Westwood in the other match.

"Padraig's a tremendous player, a real world-class player right now . . . I just wish my dad hadn't given him all the secrets," quipped Torrance, who availed of a late call-up to the event as replacement for Canada's Mike Weir and has acquitted himself beyond anyone's wildest dreams except, perhaps, his own.

After yesterday's series of surprise results, Harrington, at 15th in the world rankings, now finds himself as the highest-ranked player left in the championship. He is also the new favourite, and deservedly so. In defeating Nick Faldo on the first day, and Clarke yesterday, much of his play has been sublime and he is an accumulated 21-under-par for the 60 holes he has required to reach the semi-finals.

Indeed, one of the strangest aspects of yesterday's play was three of the four winners had been involved in Thursday's opening play - and all the recent history had indicated that those who avoid such rigours tend to go on and win. Westwood is now the only player left who can embellish such a theory.

Meanwhile, Harrington's win over Clarke also made amends for the couple of times he had lost out to him in their distant amateur days - in the Irish Close final in 1990 and that year's South of Ireland semi-final. But he claimed: "I am quite happy to record a victory over him, but I wasn't looking for any pay-back. Just because we were two Irish players didn't give the match any special edge. It was totally a case of playing against another guy. You could be playing your friend, your best buddy, and you would still go out and try just as hard to win."

His two wins to date have been achieved in quite different ways. Against Faldo, he jumped into an early lead, dominated proceedings, and never allowed his opponent into the match; against Clarke, Harrington had to scramble hard for much of the first 18 holes and, with his opponent having little luck on the greens, only took the initiative when winning the first hole of the afternoon, the 22nd, with an eagle three.

In general, though, Harrington's play has been aggressive. "I think playing aggressively suits me. I'm a player who thinks too much about things and, in strokeplay tournaments, you're thinking about the whole 72 holes, telling yourself not to do this or that. You might say, 'why not play aggressively, as if it is matchplay, all the time', but you can't do that. You have to have patience in strokeplay tournaments, go more for the middle of the green."

Two years ago, when Harrington met Montgomerie in the semi-final on his first appearance at Wentworth, it was new territory for him. "I went into that match with great confidence, and lost. Have I improved as a player since then? That's for others to judge. But I don't think I will intimidate anyone standing on the first tee . . . the way to do that is to hit it close and make lots of birdies," insisted Harrington.

His Ryder Cup captain will get to see that approach at first hand.