Toulon stand on the brink of a historic double in the Top 14 final against Castres in Paris on Saturday.
Rory Kockott's boot kept Castres in the hunt long enough to help beat Montpellier 22-19 in extra time of their Top 14 semi-final on Saturday.
Toulon kept alive their hopes of a Top 14 and European Cup double with a hard-fought 16-6 win over Racing Métro.
Rory Kockott contributed 17 points to Castres' upset 22-16 win over Clermont in their Top 14 play-off at Marcel Michelin.
Seven penalties by Jonathan Sexton earned Racing Métro a semi-final clash against Toulon in the Top 14 on Friday.
Bok flyhalf Morné Steyn missed a vital conversion which would have given Stade Français a play-off berth in the Top 14.
Toulon climbed to the top of the Top 14 log with a 46-31 win over Perpignan, while Stade Français knocked on the door of the top six by beating Bordeaux 37-23.
Bryan Habana celebrated his return to Toulon after a long injury lay-off by scoring the decisive try for a 22-20 Top 14 win over Bordeaux on Saturday.
The long-awaited return of Bok wing Bryan Habana for Toulon was put on hold in a tense match against Toulouse on Saturday.
Rory Kockott contributed 16 points to a 38-6 win for Castres over Brive as the battle for Top 14 play-off places heated up.