Castres boosted their Top 14 play-off hopes with a 16-12 victory over Bordeaux-Begles, while La Rochelle dished out a 71-21 thrashing to Pau on Saturday.
Defending champions Castres have now won eight of their last nine games in all competitions and sit fourth in the table after striking a blow to Bordeaux's bid for a top-six finish.
Second-half tries from Geoffrey Palis and Marc-Antoine Rallier along with penalties from Benjamin Urdapilleta and Rory Kockott consigned Bordeaux to defeat at Stade Chaban-Delmas.
Bordeaux could only muster three Baptiste Serin penalties and another from Matthieu Jalibert in a loss which leaves them level on points with seventh-placed La Rochelle.
La Rochelle responded to a defeat to Castres by putting Pau to the sword, scoring 10 tries in a ruthless drubbing.
Arthur Retiere amassed 18 points - including a brace of tries - and Kini Murimurivalu claimed a double as La Rochelle showed no mercy to lowly Pau.
Lyon were also ruthless in a 47-9 of bottom side Perpignan, who are almost certainly doomed after second-bottom Grenoble were 19-18 winners over Toulon - who were a man down following Raphael Lakafia's red card late in the first half.
Stade Francais beat Agen 25-22 despite having both Sekou Macalou and Jonathan Danty sent off.
