Biarritz host Amlin semi-finalists Stade Francais, while Toulon travel to relegated Lyon.
Toulon may have already secured a play-off spot but one more point would see them clinch third place and a home tie in the knockout stages.
Despite a hugely disappointing domestic season, Biarritz guaranteed their survival a week early thanks to a losing bonus point at Montpellier meaning their sole focus now is on creating some momentum ahead of the trip to England.
Biarritz welcome back inspirational skipperImanol Harinordoquy after two weeks on the sidelines as the French international back rower steps up his chase for a European title having played in the beaten Heineken Cup Final teams of 2006 and 2010.
Sylvain Marconnet, France's most-capped prop, will play his last Top 14 fixture before retiring after Friday's Amlin Final but fellow veteran Jerome Thion is being rested by Biarritz as he looks to refresh his engine for the final game of the calendar. The giant 34-year-old has already played 23 games this season, with 22 of those coming as a starting player.
Meanwhile, Toulon are resting a number of star names prior to their second Amlin Challenge Cup Final appearance in three seasons.
Captain Joe van Niekerk, openside flanker Steffon Armitage and wing AlexisPalisson are all missing from the matchday squad, while full back Benjamin Lapeyre and prop Carl Hayman have both been left out of the starting XV.
Jonny Wilkinson will start for Toulon, though, as he looks to re-discover his kicking form having missed 17 points with the boot last weekend.
Biarritz Olympique (v Stade Francais)
Bosch; Ngwenya, Barraque, Traille, Bolakoro; Peyrelongue, Yachvili; Marconnet, Heguy, Van Staden, Lund, Taele, Lauret, Guyot, Harinordoquy
Replacements: August, Barcella, Carizza, Lakafia, Lesgourgues, Gimenez, Burotu, Gomez Kodela
Toulon (v Lyon)
Rooney; Loamanu, Lovobalavu, Giteau, Smith; Wilkinson, Tillous Bordes; Emmanuelli, Orioli, Kubriashvili, Shaw, Schofield, Suta, Gunther, Fernandez Lobbe
Replacements: Ivaldi, Lewis Roberts, Botha, El Abd, Messina, Lapeyre, Cibray, Hayman