Biarritz (9) 22
Pens: Yachvili (5)
Saracens (14) 21
Tries: Ratuvou, Penny, Farrell
Cons: Jackson (3)
Saracens were denied a famous win by Dimitri Yachvili's injury-time penalty after a thrilling match in Biarritz.
Early converted tries by Kameli Ratuvou and Rodd Penney cancelled out Yachvili's opening kick and put the English side 14-9 up at the break.
After the restart, Biarritz's Samiu Vahafolau set up a counter-attack which ended with Philippe Bidabe scoring.
Andy Farrell's try in the corner seemed to have sealed victory but Yachvili's long-range effort won it.
The home fans had barely finished celebrating Yachvili's opening kick before Ratuvou took advantage of a disorganised defence to touch down in the corner.
Farrell, who was later to be the scorer, was provider for Penney with an inch-perfect chip into the corner as Saracens registered their second try, both converted by Glen Jackson.
Yachvili added two more goals in the first half but Saracens were good value for their lead, and although Biarritz added a fourth penalty, the visitors looked on the verge of stretching their lead when the home side registered their lone try.
After 10 minutes on the back foot, the French side broke away through number eight Vahafolau, who followed up his brute force charge with a fine pass to find winger Bidabe, who stretched to touch down in the corner.
Jackson slotted over his third tight-angle conversion after Farrell's try, but at the death, Yachvili was given a chance from 40 metres out and made no mistake.
Saracens coach Alan Gaffney:
"I can't say we were robbed, but I'm definitely disappointed with the result.
"It was very hard to live with the penalty count, but the last penalty was definitely legitimate - I have no doubts about it.
"I think we played some very good rugby, and scoring three tries to one in France is always a good thing. When we did have the ball I thought we did very well with it."
Biarritz: Brusque; Willemse, Bosch, Traille, Bidabe; Peyrelongue, Yachvili; Balan, Noirot, Lecouls, Thion, Couzinet, Creevy, Harinordoquy, Vahafolau.
Replacements: Cortese, Coetzee, Carizza, Cronje, Malonga, Dupuy, Masi.
Saracens: Haughton; Penney, Sorrell, Farrell, Ratuvou; Jackson, De Kock; Lloyd, Cairns, Johnston, Ryder, Vyvyan, Chesney, Hill, Skirving.
Replacements: Ongaro, Mercey, Gustard, Seymour, Rauluni, Ross, Thrower.