Montpellier hammered Castres 28-9 and Racing edged Toulouse 21-16 in their French Top 14 qualifier playoffs.
The playoff results mean the four best teams over the course of the regular season will contest the semi-finals.
On Sunday, Montpellier scored three unanswered tries at the Altrad Stadium to thump Castres and keep alive their hopes of completing the double this season. Wing Jim Nagusa, lock Paul Willemse and No 8 Pierre Spies accounted for the tries, while flyhalf Demetri Catrakilis added 13 points with the boot via two conversions and three penalties.
On Saturday, Racing 92 narrowly beat Toulouse thanks to accurate kicking of Dan Carter and Johan Goosen. Carter knocked over six penalties, while Goosen was on hand to launch a long range effort.
As the lowest-ranked semi-finalists, Racing will play Clermont next weekend, while Toulon await Montpellier.
Playoff qualifier results:
Montpellier 28 Castres 9
Racing 21 Toulouse 16
Clermont vs Racing
Toulon vs Montpellier
Photo: Bertrand Langlois/Getty Images