Racing 92 extended their lead in Top 14 with a comfortable 38-13 win over Agen at the Stade Olympique.
Struggling Agen held their own until shortly after the break. The visitors replied to an early Dan Carter penalty and converted tries from Bernard Le Roux and Virgile Lacombe with a converted George Tilsley score and two Burton Francis penalties to trail 17-10 after 43 minutes.
But the hosts turned the screw in the second half and peeled clear thanks to another Lacombe try and further scores from Joe Rokocoko and Juandre Kruger.
On Friday, Clermont Auvergne had kept the pressure on the league leaders with a 45-12 thrashing of Grenoble at the Stade des Alpes.
Noa Nakaitaci went over three times in the space of 27 minutes for the visitors, for whom David Strettle, Jonathan Davies and Enzo Sanga went over. All six tries were converted, and Morgan Parra added three more with the boot. Rory Grice notched a brace of tries for the hosts.
Bordeaux Begles kept their title hopes alive with a 48-20 thrashing of rock-bottom Oyonnax.
Adam Ashley-Cooper scored a hat trick for the hosts, while Steven Kitshoff nabbed a brace. Peter Saili and Felix le Bourhis also went over. Uwanakaro Tawalo, Alaska Taufa and Jody Jenneker touched down for the visitors.
Stade Francais' miserable defence of their Top 14 title continued with a 19-12 defeat at fellow strugglers Pau.
Three Jules Plisson penalties inside the opening 20 minutes had the Paris side leading at the break, but Paddy Butler went over shortly after to give the hosts the lead for the first time. Another Plisson kick gave Stade hope, but that was extinguished when Colin Slade added three more for Pau in the 64th minute.
The defeat leaves Stade just one place above the relegation zone.
Toulon saw their push for the title take a huge dent on Sunday when they were beaten 19-14 at La Rochelle.
The visitors had led 6-3 at half-time thanks to two Jonathan Pelissie penalties, but three second-half kicks from Zack Holmes were added to by a late Pierre Aguillon try that proved too much for Toulon to overhaul, despite an 82nd-minute try from Tom Taylor.
Brive and Stade Toulousain played out a 21-21 draw at the Stade Amédée-Domenech. A Luke McAlister try in the last minute ensured a share of the spoils for the visitors, who could have won it but Sebastien Bezy's conversion attempt sailed wide.
Elsewhere, Montpellier edged Castres Olympique 22-19, with Francois Trinh-Duc's 72nd-minute penalty proving to be the match-winning points.