The result sees Biarritz join Stade Francais, Toulouse and Leicester in the last four and a tie against the strong Parisian outfit.

``We have a very intelligent bunch of players but at halftime they knew we had committed too many mistakes,'' Munster coach Alan Gaffney said.

``To give someone like Dimitri Yachvili so many penalties was just unacceptable. Maybe we weren't patient enough. I thought we were right in the game until the last five minutes.

``All credit to the boys. We asked them to give a 100 percent, and they gave 110 percent, 120 percent. I could not have asked for anything more.''

Biarritz ceded home advantage for the Munster match by shifting the tie to Real Sociedad's football stadium in the northern Spanish Basque city of San Sebastian, the first time a European Cup match has been held in Spain.

In sunny conditions, belied by a stiff breeze and in front of a vocal 32,000 sell-out crowd, France international Yachvili slotted over an early penalty when Donnacha O'Callaghan strayed offside.

As Biarritz piled on the pressure, veteran Irish outside-half Paul Burke was caught in possession deep in his own half. A quick turnover by Damien Traille and Argentinian center Martin Gaitan outpaced Peter Stringer to cross for the first try which Yachvili converted.

It was Yachvili's trusty left boot again that gave the Basque side a 13-0 cushion with another penalty in the 30th minute. On the stroke of halftime, the scrum-half kicked another penalty to give Biarritz a 16-0 lead after flanker Alan Quinlan strayed offside.

Munster, without former New Zealand full-back Christian Cullen, influential Ireland fly-half Ronan O'Gara and Samoa center Brian Lima, came out firing in the second half and Irish international flanker David Wallace crossed for a deserved score five minutes in, crashing over for a try that Burke converted.

The game then opened up from the tight defensive game it had become in the first 40 minutes, the Munster forwards taking the game to their French counterparts, mobile prop Marcus Horgan to the fore.

Yachvili notched up another penalty in the 60th minute after Munster fullback Shaun Payne was penalized for holding on.

Burke, deputizing for O'Gara, the tournament's leading points scorer, fired over a swift reply after Thomas Lievremont infringed at a ruck to make the score 19-10.

Munster threw everything at Biarritz in the final 20 minutes, but the defense held firm to ensure no Irish participation in the Cup semifinals for the first time since 1999.