European Cup Quarter-finals: Leinster - 18 Biarritz - 13 Leinster faces bore the tentative and embarrassed smiles of those who had cheated the executioner. The relief was tangible, an acknowledgement of a moment nine and a half minutes into injury time that threatened the disintegration of a season's aspirations and hard work.

In the end, the Irish province's passage into the Heineken European Cup semi-final was an inelegant scramble, dependent upon the cool head and astute timing of full back Girvan Dempsey. His tackle on Biarritz centre Marc Stcherbina calmed the palpitations experienced by 46,000 hearts, the team yanked back from the precipice of despair.

Leinster wouldn't have deserved to lose on the evidence of the 93-odd minutes allotted by referee Steve Lander to the quarter-final but the sporting index is littered with teams filed under "U for Unfortunate". The home side didn't lop off the head of Biarritz when totally dominant in the first half, and the spurning of those chances left them vulnerable to the guillotine in the dying minutes.

Leinster coach Matt Williams probably didn't know whether to laugh or cry at the final whistle, proud and pleased that a side dogged by fractured preparation and injury niggles could create so many opportunities against the French champions, but a little miffed that they lacked the precision to finish clinically.

He conceded: "I thought we were the better team by a long way. Wayne Smith (the Northampton coach) described them as the best defence he had come across this year.

"We couldn't put them away. We missed a few kicks and got over the line three times and they were disallowed. I'm not suggesting the decisions were incorrect in any way but one more score and we would have put them away.

"I believe I'm fair in saying that it would have been an injustice on the performance of the 80 minutes. I thought we played extremely well considering our preparation. This was the game we were most vulnerable because of the lack of preparation."

Leinster certain didn't betray any anxiety at the start of the match, taking the ball through eight phases with the excellent Victor Costello involved on four occasions.

Biarritz's scramble defence was excellent and while at times it was facilitated by rank option-taking, the French side coped extremely well, especially when losing Serge Betsen for 10 minutes.

The French international was sin-binned (3-13 minutes) for having the temerity to deliberately flick the ball away from Leinster scrumhalf Brian O'Meara's hands just a few metres short of the Biarritz line. Leinster's early ascendancy was directly attributable to the input of several individuals, not least Costello, Gordon D'Arcy and Eric Miller.

Costello made the hard yards and in this task was ably assisted by Miller, whose dynamism and athleticism offered a reminder that the talent that made him one of the best forwards in world rugby is not extinguished. He tired a little in the second half but was still on hand to make tackles.

D'Arcy was a revelation, a throwback to his schooldays. His appetite for work and the clever way he popped up in the pivot position from ruck and maul made him a constant threat, his dancing feet, vision and strength a handful for the Biarritz defence.

Brian O'Driscoll conjured arguably his best performance of the new year. He broke the tackle several times, his sleight of hand and slaloming running a constant threat, while he didn't shirk defensive responsibility, one thunderous hit on replacement Ovidiu Tonita saving a certain try.

David Quinlan vied for man-of-the-match, in no way overawed by the occasion or his responsibilities. So too Leo Cullen for a work ethic that encompassed the less glamorous but essential duties.

Keith Gleeson had a superb first half in a largely excellent collective and individual performance from the pack.

While the Biarritz line enjoyed a charmed existence at times, it wasn't until the 27th minute that Leinster registered a first score. O'Meara kicked a penalty and eight minutes later converted Gleeson's try, the product of excellent play involving D'Arcy, Christian Warner and Quinlan.

O'Meara's second penalty - his strike-rate of three from six on the day was symptomatic of his recent kicking exploits - gave Leinster a 13-0 interval lead. The scrumhalf mixed some excellent line-kicking with some laboured, sluggish clearance of ball.

Leinster's concession of a silly penalty from the restart, posted by Dimitri Yachvili, breathed life into a Biarritz challenge not extinguished when Costello bullied his way over after a fine catch and drive at a lineout.

The crowd waited expectantly for Leinster to crunch through the gears but it was the French side that picked up the gauntlet.

The arrival of Tonita was a galvanising force, Leinster's concession of penalties spiralling alarmingly. Yachvili landed a superb 45-metre effort and still the home side had chances. Hickie was denied by the video referee following a great flick by Warner (the Australian had a fine match).

The match appeared to be petering out until Thomas Lievremont scored a try from a clever lineout move - Yachvili converted brilliantly from the touchline - and the realisation that there would be at least seven minutes of injury time.

O'Driscoll should have put Hickie in but instead dropped the shoulder and was grounded short.

Dempsey was next to ignore the player outside, Gavin Hickie, when a try seemed a certainty. Penalised at the ensuing scrum, Leinster watched as Biarritz probed one way then another before Tonita's pass was volleyed clear by Stcherbina.

He regathered but Dempsey had recovered, timing his tackle beautifully. Jean Michel Gonzalez was tackled and then O'Driscoll and Niall Treston rescued possession with the captain for the day kicking the ball into the East Stand, guaranteeing the victory Leinster craved.

SCORING SEQUENCE

27 mins: O'Meara penalty, 3-0; 35 mins: Gleeson try, O'Meara conversion, 10-0; 39 mins: O'Meara penalty, 13-0. Half-time: 13-0. 41 mins: Yachvili penalty, 13-3; 45 mins: Costello try, 18-3; 61 mins: Yachvili penalty, 18-6; 83 mins: Lievremont try, Yachvili conversion, 18-13.

LEINSTER: G Dempsey; G D'Arcy, B O'Driscoll (capt), D Quinlan, D Hickie; C Warner, B O'Meara; E Byrne, S Byrne, P Coyle, L Cullen, M O'Kelly, E Miller, V Costello, K Gleeson. Replacements: N Treston for Coyle 39 mins; A McCullen for Costello 68 mins; G Hickie for S Byrne 76 mins.

BIARRITZ: N Brusque; P Bernat-Salles, M Stcherbina, J Isaac, P Bidabe; J Peyrelongue, D Yachvili; M Fitzgerald, JM Gonzalez (capt), D Avril, D Couzinet, O Roumat, S Betsen, C Milheres, T Lievremont. Replacements: O Tonita for Milheres 47 mins; G Bousses for Isaac 63 mins; O Nauroy for Roumat 67 mins; M Etcheverria for Bidabe 74 mins; Bidabe for Etcheverria 82-84 mins. Sin-binned: S Betsen 3-13 mins.

Referee: S Lander (England).