Clermont secured their place in the Top 14 play-offs with a 59-18 battering of Grenoble, whose inevitable relegation to the second tier was confirmed.
It has been a season to forget for Grenoble, who knew a defeat would consign them to the drop, but second-placed Clermont only led 17-6 at the break with Alexandre Lapandry and Fritz Lee touching down.
The floodgates opened after the break, though, and Damian Penaud scored twice, while Ludovic Radosavljevic, John Ulugia, Alivereti Raka, David Strettle and Setariki Tuicuvu were all on the scoresheet in the nine-try romp that ensures a play-off spot for the visitors.
Grenoble, meanwhile, can no longer accumulate enough points to reach 12th, meaning they join Bayonne in dropping down a division.
Runaway leaders La Rochelle suffered a first league defeat since November after going down 29-25 at play-off hopefuls Lyon, who move up to fifth in the table.
In a back-and-forth encounter it was the visitors who earned the victory, with Facundo Isa touching down twice in the closing stages.
Stade Francais simultaneously boosted their own top-six hopes and damaged Pau's chances with a 51-16 hammering.
Geoffrey Doumayrou and Julien Arias each scored twice as the 2015 champions put in one of their best showings of the campaign.
Tries for Josua Tuisova and Bryan Habana along with 13 points from the boot of Leigh Halfpenny helped Toulon cement fourth place in a 23-14 triumph over Castres.
Bordeaux-Begles are one of five teams on 53 points and they needed a late try from Nans Ducuing to earn a 22-19 win at Brive, who are one point off the top six, despite residing in 11th.