Clermont missed the opportunity to enhance their position at the top of the Top 14 log when they went down 16-13 to Grenoble on Friday.
Despite putting their national players on the bench, they led 10-9 at half-time through a try by wing Julien Malzieu, a penalty and a conversion by Morgan Parra, but they were undone by a late 80m burst by Ratu Raitini, who scored under the posts.
Stade Français, now just three points behind, face Brive on Saturday.
Saturday fixtures:
Toulon vs Castres
Biarritz vs Toulouse
Montpellier vs Perpignan
Oyonnax vs Bordeaux
Racing Métro vs Bayonne
Brive vs Stade Français
Photo: Romain Lafabregue/AFP