Top 14 leaders Montpellier scored six tries in a 43-30 victory at bottom side Oyonnax and Chris Ashton grabbed a first-half hat-trick as Toulon's thumped Stade Francais 43-5 on Saturday.
Nemani Nadolo went over twice in the first half following a Benjamin Fall score and a penalty try for Vern Cotter's men, who marched into a 29-16 half-time advantage at Stade Charles-Mathon.
Gregory Fichten and Nicolaas Janse van Rensburg touched down after the interval, five-pointers from Curtis Browning, Daniel Ikpefan and Ulupano Seuteni and 15 points from Ben Botica proving to be in vain for the front-runners.
Ashton was the star of the show in Toulon's rout of sorry Stade, the former England wing claiming a treble before the interval at Stade Mayol.
Mathieu Bastareaud, Eric Escande and Raphael Lakafia also went over the whitewash as the three-time European champions moved up to fourth spot and Stade suffered a second successive mauling after being hammered by Pau last time out.
Gael Fickou helped himself to a hat-trick as Toulouse put Agen to the sword, easing to a 52-25 win at Stade Armandie.
There was also a double for Yoann Huget for fifth-placed Toulouse, who scored eight tries against the second-bottom side.
Sixth-placed Lyon struck a blow to Clermont Auvergne's play-off hopes with a 36-10 win, while Pau beat Brive 21-16.