La Rochelle maintained control of the Top 14 with a 23-13 victory over Pau which stretch their lead to 11 points at the summit of the table.
Tom Taylor started at fly-half for Pau with Colin Slade sidelined due to repeated concussions, but a change in playmaker couldn't quell a red hot La Rochelle side.
Brock James touched down inside eight minutes, with Watisoni Votu cancelling it out five minutes later. Taylor added a penalty either side of two James' penalties which saw La Rochelle lead 13-10 at half-time.
Taylor levelled shortly after the restart but a further James penalty and a Afaesetiti Amosa try with 10 minutes remaining saw La Rochelle continue their phenomenal season.
Clermont lost ground on the league leaders following a 27-24 to Racing 92 in a bad-tempered affair in Paris.
Racing looked out of sight at half-time after a dominant first-half display which saw Leone Nakarawa and Chris Masoe both cross for tries which Dan Carter converted.
The former All Blacks fly-half added two penalties as the French side led 20-0 at the break, as they took advantage of Benson Stanley's sin-binning at the end of the first quarter.
A converted Paul Jedrasiak try and a penalty from Stephen Brett gave Clermont hope, which was quickly extinguished when Stanley saw a second yellow and then a red for an off the ball tackle on the hour.
A Juan Imhoff try pushed Racing's lead out to 17 points but when Maxime Machenaud was sin-binned, it gave Clermont a glimmer of hopes in the final 10 minutes.
Clermont were awarded a penalty try and when Alivereti Raka crossed for Clermont's third try, it set up a grand stand finish but the Parisian side held on.
A David Mele drop goal two minutes from time gave second from bottom Grenoble a hard-fought 21-20 victory over Castres.
The 31-year-old scrum-half traded penalties early on with Benjamin Urdapilleta, before Mele added his first drop goal and a penalty to put Grenoble 9-3 ahead. Rory Kockott narrowed the margin with a penalty but his sin-binning on the half hour saw Mele kick the home side into a 15-6 lead at the break.
Miele added a second drop goal before tries from Yannick Caballero and a penalty try after Grenoble's Lilian Saseras was sin-binned put Castres into a slender lead with five minutes remaining.
Then with two minutes remaining up stepped Miele to land his third drop goal to secure the win.
Bordeaux-Begles kept their slim hopes of a playoff spot alive with a 20-11 win over Toulouse.
A Jean-Marc Doussain penalty and a try from French fullback Maxime Medard gave the visitors a brilliant start, leading 8-0 after 10 minutes but they failed to push on with Ian Madigan closing the gap to five points at half-time.
Doussain pushed the margin back out to eight shortly after the restart but a penalty from Madigan and two from his replacement Baptiste Serin put Bordeaux a point ahead going into the final 10 minutes.
Serin kept his nerve to stretch their lead with a penalty before Yann Lesgourgues's try four minutes from time rounded off the win.
Lyon remained in contention for the playoffs with a seven-try, 52-7 rout of Bayonne.
Argentina international Facundo Isa scored inside 60 seconds and it was soon followed by a second by Toby Arnold two minutes later.
Thibault Regard touched down before the quarter hour and Frederic Michalak added the three conversions and a penalty as Lyon held a comfortable 24-0 lead at half-time.
Bayonne saw Aretz Iguiniz sin-binned and with his departure, the floodgates opened with Carl Fearns and Toby Arnold touching down before his return. A penalty try and one from Napolioni Nalaga at the death secured an emphatic victory.
A converted Sevenaia Galala try in added time saw Brive snatch victory over Montpellier on Sunday.
Gaetan Germain was on fire with his boot for Brive and kicked two early penalties to give them a 6-0 lead.
Alexandre Dumoulin hit back with a try before the half hour but Germain continued his kicking form, splitting the posts with a penalty. When Montpellier had Paul Willemse sin-binned, Germain hit another well struck penalty to give them a 12-5 lead.
Francois Steyn kicked two penalties in reply which saw Brive's margin reduced to one point at the break.
Timoci Nagusa put the away side in front after the restart, with Germain remaining the sole source of Brive's point with another penalty as the game entered the final half hour.
Montpellier were reduced to 14 men for the second time as Yvan Reilhac saw yellow, and Germain tied the game at 18-18 apiece.
Germain kicked Brive ahead with 15 minutes remaining only for Bismarck Du Plessis to barge over the line to give Montpellier, what looked like, a narrow victory.
But with time ticking down Galala scored a try in added time to steal the victory.
In the weekend's final match, Stade Francais ended a turbulent week with a surprise 17-11 victory over Toulon.
With the prospective merger with Racing 92 having hit the buffers, attention returned to the pitch itself for Stade, who never trailed from the moment Jules Plisson gave them a fourth-minute lead with a penalty.
Plisson added three more first-half penalties before Waisea Nayacalevu touched down eight minutes into the second half to open up a 17-3 lead. Toulon could only add an uncoverted Mathieu Bastareaud try and a late penalty from Francois Trinh-Duc.