Biarritz claimed a bonus-point 26-19 win over Bath to secure top spot in Heineken Cup Pool 4 at the expense of Ulster.
The win sees the French giants claim a home quarter-final while Bath bow out of European action.
With Biarritz and Ulster level on 17 points each at the start of the final round of action, Bath knew they would have to claim a bonus-point victory to secure an unlikely route to the quarter-finals.
But they came up against a fired-up Biarritz outfit who were fighting for their own European fate.
And they got off to a flying start with a Dimitri Yachvili try after five minutes before Iain Balshaw grabbed tries either side of half-time.
Stuart Hooper handed Bath a glimmer of hope but it was short-lived with Takudzwa Ngwenya racing clear for the bonus-point try after 63 minutes.
Tom Biggs struck with two tries for Bath in the last 10 minutes but it was not enough as Biarritz marched into the knockout stages.
England’s Olly Barkley could have given Bath the perfect start but he struck the right post with a penalty after just five minutes.
It got worse five minutes later when Bath shot themselves in the foot. Barkley’s attempted clearance was charge down by French international Yachvili. The terrier-like scrum-half quickly gathered the ball to race clear and score. He then added the conversion to give his side a 7-0 lead.
The hosts extended their lead after 18 minutes when Bath old boy Balshaw celebrated a new contract with the French giants with a second touchdown. The former British Lion received the ball out wide and combined with Dane Haylett-Parry to claim the hosts’ second try.
Nick Abendanon saved a probable third try but the hosts continued to press in the closing stages of the half and had several close-range scrums, which saw Duncan Bell sent to the sin-bin, but Bath held strong and the score remained 14-0 at the half-time.
Bath got off to a wretched start in the second half with Biarritz grabbing a second Balshaw try. Biarritz made several attacks through the middle, the ball was spread wide and, despite Luke Watson getting a hand to Yachvili’s pass, the ball fell to Balshaw who stepped inside Abendanon to score.
But the West Country giants kept fighting and hit back from close range after 46 minutes. After several phases, second row Hooper was on hand to crash over. Barkley was unable to add the conversion and the score remained 21-5.
But Biarritz hit back with the crucial bonus-point try thanks to Zimbabwean-born United States flyer Ngwenya.
Yachvili, a constant thorn in the side of Bath, threw a long pass out to Marcelo Bosch and the centre sucked in three defenders to create the space for Ngwenya. The wing raced clear to score in the corner to restore his side’s 21-point lead, although Yachvili failed to land the conversion.
Biggs grabbed two late consolation tries which Sam Vesty converted but it was not enough for Steve Meehan’s men.