Biarritz cruised into the last eight with a clinical demolition of Saracens in the winner-takes-all tie in France.
HEINEKEN CUP POOL 4
Biarritz: (19) 43
Tries: Arramburu, Gobelet, August, Brusque, Bidabe, Peyrelongue
Cons: Yachvili (4), Dupuy
Saracens: (13) 13
Pens: Jackson (2)
The French side ran in six tries in an impressive all-round display, capped by the assured running of their backs.
Tries from Federico Martin-Arramburu, Jean-Baptiste Gobelet and Benoit August gave Biarritz a 19-13 at the break.
Nicolas Brusque, Philippe Bidabe and Julien Peyrelongue added further tries, while Saracens scored a solitary first-half try from prop Kevin Yates.
Biarritz scrum-half Dimitri Yachvili slotted four conversions, while his three missed kicks saved Saracens further blushes.
The visitors were hit by the late withdrawal of forward Ben Skirving but struggled to keep pace with the French side and were further hampered by the sin-binning of Simon Raiwalui and Dan Scarbrough either side of half time.
Biarritz clinched pool four with 24 points and sank Saracens hopes of qualifying as a best runner-up.
Saracens opened the scoring with a Glen Jackson penalty but they were soon fighting fires after Biarritz ran in two quick tries.
Centre Arramburu crossed on 12 minutes after slick back play before wing Gobelet rounded off another well-executed move after Arramburu's dummy opened up the Saracens defence.
The visitors responded soon after with a score under the posts for prop Yates after Jackson's break.
But Biarritz added a third try on 34 minutes when Yachvili put hooker August in on the blind side from a close-range scrum.
Jackson's late penalty narrowed the gap to six points at the break but the English side lost Raiwalui to the sin-bin for a high tackle shortly before the whistle.
Biarritz's fourth try came moments after the interval, when Brusque capped yet another successful back venture before the impressive outside centre Bidabe sliced through for a fifth.
Saracens' troubles were compounded when Scarbrough was sin-binned for an off-the-ball tackle on Brusque.
And the home side sealed the win with a late score from fleet-footed fly-half Peyrelongue.
Saracens rugby director Steve Diamond:
"Biarritz are a good team, and they ran amok. We had two or three backs injured, and ended up with back-row forwards in the back-line," he said.
"We were beaten by a far better side. They run good angles, but they also play with a lot of patience and wear you down.
"To a certain extent it was men against boys, but while I am disappointed with the result, I thought we stuck at it.
"We've now got to concentrate on the league and Heineken Cup qualification for next season is what we are after."
Biarritz: Brusque; Gobelet, Bidabe, Martin Arramburu, Bobo;
Peyrelongue, Yachvili; Balan, August, Lecouls; Thion, Couzinet;
Dusautoir, Harinordoquy, Lievremont.
Replacements: Lison for Martin Arramburu (44), Dambielle for Bobo (76), Dupuy for Yachvili (69), Lealamanua for Balan (58), Noirot for August (64), Olibeau for Thion (40), Betsen for Lievremont (63).
Saracens: Bartholomeusz; Johnston, Castaignede, Harris,
Vaikona; Jackson, Rauluni; Yates, Byrne, Broster; Raiwalui,
Vyvyan; B Russell, Seymour, Chesney.
Replacements: Sorrell for Castaignede (24), Scarbrough for Harris (53), Liffchak for Yates (70), Cairns for Byrne (66).
Not used: Kyriacou, Dickens, Mercey.
Sin bin: Raiwalui (40), Scarbrough (62).
Referee: A Lewis (Ireland).