Brent Russell scored the only try in the Top 14 fixture between Mont-de-Marsan and Clermont but the visitors still lost 12-11.
The Clermont winger recently made the move across the English Channel to join former Springbok team-mate Marius Joubert. His characteristic game-breaking ability was not enough to save Clermont on this occasion, as wayward kicking by Fijian Seremaia Bai allowed Mont-de-Marsan to sneak a win.
Shaun Sowerby’s Toulouse stayed top of the table with a convincing 32-11 win over Bayonne.
Top 14 results:
Toulouse 32 Bayonne, 11
Bourgoin 23 Castres 9
Mont-de-Marsan 12 Clermont Auvergne 11
Perpignan 9 Montauban 6
Dax 13 Toulon 6
Stade Français 32 Biarritz 13
Brive 22 Montpellier 9