Biarritz booked a place in the Amlin Challenge Cup Final with a 19-0 win over French rivals Brive in their semi-final at Parcs des Sports Aguilera on Saturday.
Biarritz will now meet Toulon in the final at Twickenham Stoop where the winners will be guaranteed a place in next season's Heineken Cup.
On a soaking wet pitch and in driving rain, the hosts adapted better to the conditions and took their chances in front of goal.
Centre Damien Traille scored the only try of the game with all the rest of the points coming via the boot of scrum-half Dimitri Yachvili.
Outmuscled at scrum time, Brive were unable to capitalise on their numerous opportunities, especially in the second half.
With both clubs out to save their respective seasons, the tension bubbled over after just 30 seconds with the first of a handful of punch ups.
Biarritz were camped deep in the visitors' territory for much of the opening quarter and Yachvili was able to kick BO into a 6-0 via two penalties.
The Basques stretched their lead just before the half-hour mark when Traille beat Ronnie Cooke to a bomb from fly-half Marcelo Bosch that landed inside the Brive in-gaol area. The French international touched down and the TMO gave the rubber stamp for the game's first and only try.
Yachvili added the extras to put Biarritz 13-0 ahead and they held that advantage until the half-time break.
Brive dominated the opening exchanges after the interval but were denied points when centre Riaan Swanepoel missed his second attempt at goal.
Les CorrÃ©ziens continued to ply the pressure and with Swanepoel off-target at the tee and Mathieu Belie off injured, they chose to push for a try after a long period camped on the BO line.
But the Biarritz defence was not to be moved and Yachvili put the result beyond doubt with two more penalties as Biarritz reached their third European final in six years.
Pens: Yachvili 4
Red card: Barozzi (Brive - 81st min - headbutt)
Biarritz: 15 Iain Balshaw, 14 Taku Ngwenya, 13 Dane Haylett-Petty, 12 Damien Traille, 11 BenoÃ®t Baby, 10 Marcelo Bosch, 9 Dimitri Yachvili, 8 Raphael Lakafia, 7 Talalelei Gray, 6 Benoit Guyot, 5 Manuel Carizza, 4 JÃ©rÃ´me Thion, 3 EugÃ¨ne Van Staden, 2 Arnaud Heguy, 1 Sylvain Marconnet.
Replacements: 16 Benoit August, 17 Yvan Watremez, 18 Francisco Gomez Kodela, 19 Erik Lund, 20 Magnus Lund, 21 Julien Peyrelongue, 22 Jean-Pascal Barraque, 23 Charles Gimenez.
Brive: 15 Mathias Atayi, 14 Ronnie Cooke, 13 Riaan Swanepoel, 12 Jamie Noon, 11 Sevania Galala, 10 Mathieu Belie, 9 Augustin Figuerola, 8 Antoine Claassen, 7 Vincent Forgues, 6 Simon Azoulai, 5 Olivier Caisso, 4 Retief Uys, 3 Alexandre Barozzi, 2 Iuri Natriashvili, 1 Jefferson Poirot.
Replacements: 16 Virgile Lacombe, 17 Pablo Henn, 18 Pat Barnard, 19 Julien Le Devedec, 20 Arnaud Mela, 21 Poutasi Luafutu, 22 Shane Geraghty, 23 Arnaud Mignardi.
Venue: Parcs des Sports Aguilera
Referee: George Clancy (Ireland)