Lyon and La Rochelle both progressed to the Top 14 semi-finals after claiming wins over Montpellier and Racing 92 respectively.
La Rochelle will travel to Toulouse, who finished the season top of the table, while Clermont, who finished second, will host Lyon.
Lyon, with No 8 Deon Fourie, lock Hendrik Roodt and Etienne Oosthuizen in their ranks, will be looking for their first ever Top 14 title.
Ex-All Blacks centre Charlie Ngatai was the match-winner, scoring a crucial try in the 69th minute which put the home side into the lead going into the closing stages.
Up until that stage, Montpellier had led for most of the game thanks to a converted try from Aaron Cruden. Scrumhalf Benoit Paillaugue kicked two penalties for the visitors to help them into a 13-11 half-time lead, with Lyon responding through a try from centre Pierre-Louis Barassi.
That set up a nail-biting second half where Lyon flyhalf Jonathan Wisniewski traded penalties with Cruden to make it 16-14 to Monpellier, before Ngatai scored the decisive try.
In the first semi-final on Friday, La Rochelle, with flank Wiaan Liebenberg in their starting lineup, stunned Racing 92 with a tense 19-13 win in Paris.
It was another New Zealander in Ihaia West who had the biggest influence, slotting four penalties and a conversion to give La Rochelle the victory.
Photo: JEAN-PHILIPPE KSIAZEK/AFP/Getty Images