Five-time champions and two-time Heineken Cup runners-up Biarritz's defeat to Perpignan on Saturday confirmed their relegation from the Top 14, ending an 18-year stay in the elite division.
Biarritz, founded in 1913 and boasting legendary international full-back Serge Blanco as president, had to win away at Perpignan to keep their faint chances of survival alive but suffered a 16-10 loss.
Despite boasting the talents of skipper Imanol Harinordoquy and Dimitri Yachvili, the signs of decline were evident in recent seasons with ninth-place finishes in 2012 and 2013 making the title triumphs of 2002, 2005 and 2006 look distant memories.
On Saturday they were holding on at 10-10 at the interval against Perpignan.
Welsh centre Aled Brew gave them a confidence-boosting edge with an 11th-minute try converted by Julien Peyrelongue, but Perpignan's English winger Richard Haughton scored a try on 20 minutes, converted by Welsh star James Hook.
Hook had already kicked an early penalty with Peyrelongue also knocking over an injury-time three points for 10-10 at the break.
However, Hook succeeded with two second-half penalties to give Perpignan victory and send Biarritz into the second division despite four more matches still to play.
Blanco and Biarritz manager Laurent Rodriguez left the Stade Aime-Giral by a side-door with just the 33-year-old Yachvili, the 59-capped scrum-half facing the media.
"We were practically down, now it's definite," said Yachvili, who has been at Biarritz through thick and thin since 2002.
"We have four games left, we will play for the jersey's honour. I am sad and disappointed, but that's life."