Biarritz made it successive wins in the Top 14 thanks to a 16-11 victory over Agen at Parc Des Sports D'Aguilera.
Agen came out of the blocks firing with a try on three minutes from number eight Opeti Fonua, with the conversion missed by Ben Seymour.
The new signing from Australia was on target on eighteen minutes with a penalty before Biarritz clicked into gear with a Julien Peyrelongue three points preceding hooker Anthony Hegarty's try. Peyrelongue's extras and a 40th-minute penalty gave the home side a five-point half-time lead.
Unfortunately the Parc Des Sports D'Aguilera crowd were treated to just three points for either side in the second-half in a result that lifts BO above Grenoble, if only temporarily.
Pen: Peyrelongue 3
Pen: Seymour, Barnard
Referee: Mathieu Raynal
Assistant referees: Cyril Lafon, RenÃ© Bordeneuve
Television match official: Philippe Bonhoure