Matt Williams is a perfectionist, a trait common to all top coaches. While suggesting that the last two weeks have brought on his Leinster team considerably, he couldn't help recalling wistfully those heady days of January. The team then was match hardened and battle sharp.

It's not that he's unhappy in the lead-up to tomorrow's game at Lansdowne Road, describing the preparation in the fortnight between the Biarritz game and this semi-final as "very good", adding that "the attitude of the players has been exceptional", but he considers the final on May 24th, should Leinster make it, as the optimum time-frame for his side to peak. Taken at face value it suggests the team may not be as slick and cohesive as he'd like.

The players' demeanour and body language bespoke a relaxed squad. They seemed more inclined to view the Biarritz victory in the half-full glass analogy than the half-empty one that was adopted in some quarters. They were guilty of squandering chances and the final throes of that match would have been enjoyed only by cardiologists, but it shouldn't mask the excellence of the rugby produced in the first 60 minutes.

If Leinster replicate the approach work and tag on the requisite ruthlessness in capitalising on the opportunities against Perpignan they'll win, and win well.

Perpignan have arrived in the semi-final in a relatively low-key manner. Despite their excellent home wins over Gloucester and Munster, they only scraped past Viadana, 39-35, in their final pool match to guarantee qualification.

If the travelling support was to prove a barometer of their ambition for the quarter-final against Llanelli at Stradey Park - about 75 supporters - Perpignan shouldn't have bothered to leave home. Without demeaning their 26-19 victory, Llanelli flanker Daffyd Jones' utter stupidity in getting sent off early on had a pivotal impact on the proceedings.

Perpignan have been lauded for their forwards but they are not one-dimensional. The fact rain is forecast won't upset them. They will use their pack to try to grind down their opponents, make them work at every scrum and in the lineout and look to use their excellent maul.

They will try to force Leinster to commit forwards to rucks and mauls and then pursue a wider approach through their Australian pivot, Manny Edmonds. Edmonds essentially likes to put the ball through the hands, whether it's linking with the pack or air mailing the ball to the wings.

Blindside flanker Gregory le Corvec was superb the last day in a fine back row that includes captain Bernard Goutta and former- Ireland Schools international and Canuck Test player Phil Murphy. Second row Rimas Alvarez-Kairelis is a proven try scorer, while the front row, although without the injured loosehead Renuad Peillard, are noted scrummagers.

The Catalonian club's style is rugged but in former French international full back Jean Marc Souverbie, they possess a cutting edge. Two further internationals, Christophe Porcu and veteran Marc Del Maso, are on the bench.

Leinster's first inclination will be to keep a high tempo to the game, try to superglue as many Perpignan forwards to the bottom of rucks. From those who have seen Perpignan regularly the suggestion is that David Quinlan - Shane Horgan has a fitness test this morning to see if he can take his place on the bench - and Brian O'Driscoll could make significant inroads in the centre.

Denis Hickie needs to loose whatever mental or physical shackles he has been bound by recently and remember what made him an outstanding international wing. Gordon D'Arcy needs to show the same work rate and vision as the last day. Christian Warner had a fine game the last day but he'll probably need to vary his patterns a little more.

Up front, the returning Reggie Corrigan will charge his fellow forwards with producing exemplary setpieces and showing an appetite for what is bound to be a very physical contest. Victor Costello will again be expected to make the hard yards.

Leinster's priority must be to take their chances, whether place-kicking or try-scoring opportunities. A good start and the Irish province could treat their supporters to a good afternoon. They're certainly good enough to do so.

REPLACEMENTS

LEINSTER: Niall Treston, Gavin Hickie, Aiden McCullen, Aidan Kearney, Brian O'Riordan, Nathan Spooner, Shane Horgan.

PERPIGNAN: M Del Maso, A Moreno, C Porcu, J Daniell, L Mallier, J Basset, N Laharrague

Referee: Nigel Williams (Wales).