Exeter Chiefs will face the Heineken Cup champions for the second successive season after they were drawn with Toulon.
Castres booked their place in the Top 14 semi-finals after a 22-12 victory over Montpellier at Stade Pierre-Antoine.
A losing bonus point for Montpellier in Bayonne was enough to eliminate Perpignan from the race for the play-offs.
Second takes on third in the pick of the Top 14 fixtures with Clermont set to entertain Toulouse on Saturday.
Racing-Métro secured a crucial result in the race for the Top 14 play-offs with a bonus-point win over Mont-de-Marsan.
Clermont Auvergne became the first team into the Heineken Cup semi-finals with a 36-14 win over Montpellier.
Clermont are the favourites to book their place in their Heineken Cup semi-finals when they do battle with Montpellier.
The venues for this season's Heineken Cup semi-finals have been confirmed by European Rugby Cup.
A last-gasp try from Vincent Clerc saw Toulouse claim a 27-26 win over Racing Metro, ending the Parisians' winning run.
Racing Metro picked up a priceless away win as they edged past Montpellier 17-15 at the Stade Yves du Manoir.
Leaders Toulon will take on fourth-placed Castres on Friday in the pick of the weekend's Top 14 action.
Stade Francais remain in the Top 14 play-off picture after a backs-to-the-wall victory over Bordeaux.
The Top 14 action gets underway on Friday when Toulouse look to maintain their impressive home record over Perpignan.
There are plenty of intriguing ties in the Top 14 this weekend, starting with Clermont travelling to Racing on Friday.
Aviva Premiership outfit Worcester have agreed a deal to sign Argentina international hooker Agustin Creevy.
Perpignan stayed in the race for the Top 14 play-offs thanks to a hard-fought 26-19 win over high-flying Clermont on Friday.
The dates for the Heineken Cup quarter-finals have been confirmed.
Toulon full-back Delon Armitage has been handed an eight-week ban after being cited for a tip tackle.
Montpellier thrashed Toulon 23-3 to join their visitors in the Heineken Cup quarter-finals.
Montpellier require two points from their final pool game against Toulon to book a place in the quarter-finals.