Bath Rugby's Heineken Cup Pool Four campaign kicked off with an agonising 11-12 defeat against last season's runners-up, Biarritz Olympique, at the Recreation Ground.
Bath had led from the fourth minute to the 55th - and responded to going behind for the first time in the contest by hitting back to regain the lead with 12 minutes to play.
But a 71st-minute Dimitri Yachvili penalty, his fourth from four attempts in the match, after David Wilson had been sent to the sin-bin for knocking the ball out of the scrum-half's hands as he prepared to pass, gave Biarritz a lead they preserved until the final whistle.
Despite denying their opponents a try, it was another tale of late Heineken Cup disappointment against top-class French opposition for Bath, having suffered at the hands of Toulouse two years ago and Stade Francais last year.
Head coach, Steve Meehan, said: "We played a very good first half and got all the decisions right - but then the technical penalties went against us in the second half and, when we did have an opportunity to get on the front foot, we turned over too early.
"Even with four minutes to go, we had an opportunity to win the match and we didn't take the chance. The feelings are very mixed, because it was a better performance than the previous week, but to come up short like that is very frustrating and disappointing."
Bath had taken the lead through an Olly Barkley penalty - and followed up the early score with a well-worked Michael Claassens try to give them an 8-0 lead after as many minutes.
But, despite leading 8-0 at half-time, Biarritz - as their pedigree suggested they might - began to claw their way back into the match after the break. Yachvili landed the first of his penalties on 43 minutes and cut Bath's lead to two points with another on 51 minutes.
The France No 9 then edged his side into the lead after 55 minutes, only for Barkley to reply with a long-range effort to restore the Bath advantage. But Yachvili held his nerve after Wilson had seen yellow to make it 11-12.
Bath then heaped pressure on the Biarritz line as they strove to reclaim the advantage and get off to a winning start in Pool Four, but were unable to find a way through the well-organised Basque defence.
"We worked harder as a team together this week than we did last week against Gloucester, so that's a positive," added Meehan. "Also, when we are doing things correctly on the field - the way we are training - then we're a very good side. The try we scored came from some very basic rugby that was done very well and very efficiently. We've just got to transfer more of that into the game."
Barkley kicked Bath into the lead after Claassens was caught by a high tackle - before the scrum-half increased the advantage with a try. Bath secured line-out ball on the left and switched play right, first with the crash ball, before deploying their renowned craft and guile out wide. Claassens found Barkley, whose clever pass to Nick Abendanon created the opening, and the full-back released Matt Carraro, who was tackled just short of the line. From the resulting ruck, Claassens picked up and went over to give his side an 8-0 lead.
Abendanon then had to show his defensive prowess after Bath had been intercepted in attack and been caught on the counter-attack. Michael Bond broke down-field and passed to the lightning quick Takudzwa Ngwenya - but Abendanon somehow caught the winger, brought him down, and Bath regrouped and won turnover ball.
The first half came to a close with Bath in the ascendancy, even if they could not force another score before the break, but they did not enjoy the same dominance after the interval.
Instead, the streetwise Biarritz forced Bath into a number of penalties for technical offences, and the reliable Yachvili took full advantage. He did not miss a single shot at the sticks, but instead kept the scoreboard ticking over to frustrate Bath and take the game away from them.
From being 8-0 down at half-time, Biarritz were 9-8 up after 55 minutes - and that was after having what they felt was a try by No 8 Raphael Lakafia ruled out by the television match official for a double movement. Julien Peyrelongue missed a drop goal shortly after Yachvili's third penalty - before Barkley kicked Bath back into the lead from long-range after a penalty was awarded at a scrum.
Replacement Damien Traille then failed with a drop-goal attempt of his own, before Yachvili took full advantage after prop Wilson was sent to the sin-bin to make it 11-12 with nine minutes left.
Bath still had a gilt-edged opportunity to win the match late on - but tried to build phases close to the Biarritz line, rather than attempting a drop goal, and eventually knocked on in contact to relieve the pressure on their visitors. There was still time for Traille to attempt another drop goal, which he missed, but Biarritz held on for victory.