Agen all but secured their Top 14 status with a 29-11 win at second-bottom Grenoble and leaders Toulouse inflicted an 83-6 thumping on pitiful Pau on Saturday.
Grenoble now look set to be heading for a relegation play-off after they were beaten by the team they were striving to reel in.
Agen opened up a 10-point advantage over Grenoble with two matches remaining with tries from Romain Briatte and Clement Laporte, while the trusty boot of Leo Berdeu added 19 points.
Bastien Guillemin's five-pointer had given second-bottom Grenoble an 8-0 lead, but disciplined Agen rallied to pull off back-to-back victories.
Pau were humiliated at Stade Ernest Wallon a fortnight after they were thumped 71-21 at La Rochelle.
Toulouse scored 13 tries in a ruthless demolition job, Thomas Ramos claiming a double and nailing seven conversions for a 24-point haul.
La Rochelle moved up to third with a 30-21 home victory over Toulon, with Kini Murimurivalu, Tawera Kerr-Barlow and Elliot Roudil touching down.
Montpellier boosted their bid for a play-off place with a 12-9 win at Castres, while Peceli Yato grabbed a hat-trick in a 35-13 success for second-placed Clermont Auvergne over relegated Perpignan.