Lee Westwood has a two-hole advantage over the tournament favourite Colin Montgomerie going into the final 18 holes of the World Matchplay championship to be played to its conclusion this morning.

Ahead from the first hole of the final, delayed until yesterday afternoon, Westwood's solid short game and putting looked to have dented Montgomerie's almost unshakeable belief that he has only to drive into Wentworth to have the engraver inscribing his name.

However, although Westwood chipped stone dead from the rough for a birdie at the par-five 18th, Montgomerie got in the final blow of the day by rolling in a monster putt of almost 40 feet for the eagle that took the hole and, importantly, kept him in touch. If the scoring in matchplay, with its premium on attacking, tends to be lower than strokeplay then a round of 63 from Westwood and one of 65 from Montgomerie represents awesome golf nonetheless.

Earlier, though, in a semi-final restricted by torrential rain to just a dozen holes on Saturday, Westwood, who by the end of play yesterday had played 42 holes on the day, declared himself "a bit shell-shocked, really" to have come back from two down with three holes to play against Ernie Els, three times the winner of this tournament.

That is just not done. But he holed three successive birdie putts of around 10 feet, the last after missing the green with his five-wood second, and leaving short his chip that was desperately difficult from clingy rough, with no more than 10 feet of green with which to work. Meantime Els had hit the green in two, lagged his first putt to what he thought would be gimme range but then failed to hole the two-footer that, as it transpired, he needed to keep the match alive.

"It was a bizarre finish, almost surreal," Westwood admitted. "I have seen lots of short putts missed on that green, but there was no way I expected him to miss it."

In the other semi-final, Montgomerie, three up on Vijay Singh after 14 holes overnight, hit his first approach shot of the day, an eight iron, close enough for a concession and a four-hole cushion . With that, he felt, he was playing well enough to hold off anything the man from Fiji could throw at him. Eventually he ran out winner by 5 and 4 and 26 under par for 68 holes.

Westwood had a phenomenal day. He did not drop a shot and made nine birdies in 24 holes to complete his semi-final and a further nine in the afternoon for his best round of the week. For the first eight holes cut was followed by thrust, the lead going first to Westwood, then to Montgomerie and back to Westwood again when he holed from eight feet.

Montgomerie might have squared things at the 11th - ought to in his own mind - but followed a misreading of his own eight-footer with a passable imitation of Victor Meldrew. The par-five 12th was halved in birdies but Westwood increased his lead on the next by hitting a six iron into the fringe round the green and holing from 12 feet.

Pars at the next two holes were followed by shared birdies at the 16th, Montgomerie holing manfully from 11 feet and Westwood from half that distance. But although both players were just short of the long 17th in two, it was Westwood who was able to get up and down to take the hole and stretch his lead.

"I think I was 13 when I played as many holes as that in a day," said Westwood. "In fact, it was probably 54 I played then.

"I think I'll sleep well, but I feel fresh mentally and ready to try to finish this off. I didn't come here not to win."

Montgomerie opted to keep his thoughts to himself after coming off second best against the man who is also in sight of ending his seven-year reign as European number one in the next month.

Until he came up against Westwood, there had been an air of invincibility building up around Montgomerie on the West Course - scene not only of his victory last year, but also of success in the last three Volvo PGA championships.

Final (prefix denotes seeding): (1) C Montgomerie (Sco) 2 down to (3) L Westwood (Eng) (after 18 holes)

(match resumes at 8.0 a.m. today)