Paul Sackey scored twice as Toulon beat Top 14 leaders Toulouse to keep their play-off hopes alive on Saturday.
Clermont broke their duck on the road this year with victory over a disappointing Stade Français side in Paris.
Racing Métro are in danger of missing out on automatic qualification for the semi-finals after crashing to their second consecutive loss, going down in Perpignan.
Montpellier's unbeaten record at home came to an end against Bayonne, who are now back in the race for the play-offs.
Biarritz bounced back from the Heineken Cup heartbreak last weekend by running eight tries past Brive for a bonus-point win.
Castres took a step closer to a place in the play-offs with victory in Bourgoin, but will be disappointed not to have picked up a bonus point.
On Friday, Agen booked their place in the top flight next year with victory over La Rochelle, who are now almost certain to be relegated.
La Rochelle 19-29 Agen
Stade Français 12-20 Clermont
Bourgoin 22-33 Castres
Perpignan 23-16 Racing Métro
Biarritz 52-26 Brive
Montpellier 17-22 Bayonne
Toulon 21-9 Toulouse
Stade Français Paris 12-20 ASM Clermont Auvergne
Stade de France, Paris
It turned out to be a disappointing game at the Stade de France. An error-strewn display from both sides was symptomatic of their respective seasons.
Clermont were easy winners in the end, finally getting their second win on the road and - more importantly - maintaining their place in the top six.
A mediocre first half ended with Clermont leading 10-3 thanks to a try on the quarter-hour mark from Fijian wing Kini Murimuriva
Lionel Beauxis landed a drop for the hosts in the third minute but the uninspired Parisians hardly threatened again.
In the second period, the visitors extended their lead to 17-6 when Brock James's cross-field kick found Julien Malzieu unmarked out wide.
Stade Français scrum-half Julien Dupuy had hit the target with one penalty but missed a couple of others so Beauxis took over the kicking responsibilities and reduced the gap with two three-pointers to 17-12.
Clermont would have the last laugh though, as James slotted a late penalty to assure victory for les Juanards
USA Perpignan 23-16 Racing-Métro 92
Stade Aimé Giral, Perpignan
Racing-Métro maintained second place in the standings thanks to a losing bonus point snatched in the 80th minute when Sébastien Chabal bolted 60m to score a try on the counter attack.
After booking their place in the Heineken Cup semi-finals last weekend, Perpignan found the resource to put in a very big performance to stay in the play-offs race, although they still lie eighth - three points off the pace.
The battle up front was ferocious in the first half, especially at scrum time. USAP led 6-3 at half-time but Racing drew level immediately after the restart.
Perpignan moved clear however thanks to tries from full-back Joffrey Michel and centre Rudi Coetzee.
Biarritz Olympique 52-26 CA Brive Corrèze
Parc des Sports d'Aguilera, Biarritz
A week after crashing out of Europe, Biarritz confirmed they are still in the running for silverware this year with a demolition job of Brive.
Eight tries in a dominant display was just what the doctor ordered as the Basques rise to fifth in the standings.
Number eight Raphael Lakafia and his loose forward partner Magnus Lund score two tries each while centre Marcelo Bosch, flank Wenceslas Lauret and wings Ilikena Bolakoro and Takudzwa Ngwenya all got one each.
Brive where 33-0 down when South African flank Gerhard Vosloo scored the first of his two tries for the visitors in the second half.
Late tries for scrum-half Shaun Perry and Jean-Philippe Bonrepaux added some respectability to the Brive scoreline but they failed to pick up the losing bonus point that would have assured their safety and relegated La Rochelle.
RC Toulon 21-9 Stade Toulousain
Stade Vélodrome, Marseille
Toulon might have been knocked out of the Heineken Cup last week but they're still hanging on in the Top 14 by the tips of their fingers.
Despite saying they didn't care about the result, Toulouse sent a very strong team to Marseille and had the better of the opening exchanges to lead 6-3 at the break as Florian Fritz slotted tow penalties while Jonny Wilkinson landed a drop for the hosts.
Les Toulonnais, visibly pumped up to the point of overdoing it, where saved by two tries in the space of four minutes from Paul Sackey.
Gabi Lovobalavu escaped Fritz before chipping ahead for the former England winger for the first try before Sackey wriggled out of four tackles to score the second.
The victory maintained Toulon's perfect Top 14 record at French football champions Marseille's Stade Velodrome with their fifth successive win there.
However, Toulon have a tough final two matches as they host 2009 champions Perpignan - who knocked them out of the European Cup last Saturday - and then travel to Montpellier in the final match.
Toulon president Mourad Boudjellal was relieved that the side, who he has bankrolled for millions of euros, had rebounded from the European Cup disappointment and kept their hopes alive of prolonging their season.
"There is little to say about the first 50 minutes! We just sat back and watched them play," said Boudjellal.
"Then the Toulon magic clicked into gear... I think that the unexpected energy of Sackey surprised them."
Montpellier HR 16-22 Aviron Bayonnais
Stade Yves Du Manoir, Montpellier
Montpellier chose the worst possible moment to concede their first defeat at home this season as they drop to sixth in the standings with Toulon and Perpignan breathing down their necks.
The hosts will harbour many regrets having had victory within reach, but despite their domination for large parts of the match they couldn't round off their opportunities.
Guillaume Bernad score another for the Basques but the pressure applied by Montpellier allowed them to keep the scoreboard ticking with penalties.
Montpellier led 14-12 at half-time but some poor place-kicking saw them fall behind as Benjamin Boyet showed them how it's done, hitting a 50m penalty.
Bayonne centre Sam Gerber snatched victory for the visitors in the 70th minute with his seventh try in six games.
CS Bourgoin-Jallieu 22-33 Castres Olympique
Stade Pierre Rajon, Bourgoin
A crazy game that saw seven tries , the ref get injured, and some creative time keeping!
In the end Castres came out on top, outscoring their hosts four tries to three for their second win on the road this season.
Castres wing Mathieu Nicolas score on either side of half time as the visitors generally controlled the game having led 18-5 at the break.
CO move up to third in the standings, just one point behind Racing.
Stade Rochelais Atlantique 19-29 SU Agen
Stade Marcel Deflandre, La Rochelle
Agen assured themselves of a place in the top flight of French rugby next season with a hard-fought victory on Friday.
The result almost means that relegation is near-unavoidable for La Rochelle.
In a ding-dong battle that went right down to the wire, Agen secured victory in the very last minute when Sylvère Tian broke clear for a counter-attacking try.