Sharp-shooting Melvyn Jaminet helped Toulon power past Castres 52-23 in Saturday's French Top 14 play-off to set up a semifinal clash with Bordeaux-Begles next weekend.
Jaminet scored the first of Toulon's six second-half tries, adding a further 22 points with his boot.
Castres had kept the home side on their toes in an evenly-matched first half, with only two points the difference in Toulon's favour at halftime.
But they were swept aside after the break, with Jaminet's 50th minute try opening the floodgates for touchdowns from Baptiste Serin, Facundo Isa, Ben White, Ma'a Nonu and Jiuta Wainiqolo.
On Friday, Bayonne crushed Clermont with a dominant 20-3 win in the first play-off to set up a semifinal showdown with reigning record 23-time champions Toulouse.
Returning to the knock-out stage of the French championship for the first time in 33 years, Bayonne mastered the wet conditions best to remain undefeated at home this season.
Clermont, champions in 2010 and 2017, never got into the game which was played in stormy weather with persistent rain preventing play from developing.
Bayonne face Toulouse next Friday in Lyon, with Toulon taking on Bordeaux-Begles 24 hours later.
The Top 14 final takes place on June 28 in Paris.
Tommaso Allan booted a late penalty earlier Saturday as Perpignan preserved their Top 14 spot by beating Grenoble, losers in French rugby's second-division final, 13-11 in a promotion playoff.
In a tense game of repeated lead changes, Romain Trouilloud had booted the hosts ahead with sixth minutes to play. The Perpignan pack forced one last penalty and Allan converted.
Perpignan had finished 13th out of the 14 teams in the top flight to give themselves one more chance, away to the losers of the D2 final.
Grenoble topped D2 but had lost the final of the six-team playoff for the third time to force them into another do-or-die match.
The defeat also marked the second time in three years that Perpignan had beaten Grenoble in the playoff.
