Perpignan stayed in the race for the Top 14 play-offs thanks to a hard-fought 26-19 win over Clermont on Friday.
The result is only Clermont's fourth loss in all competitions this season and allows Toulon to move seven points clear at the summit of the standings.
But the league leaders didn't have it all their own way on Friday either as they failed to pick up the expected bonus point against lowly Mont-de-Marsan.
In the capital, Stade FranÃ§ais also kept their play-off hopes alive with a big win over Grenoble.
Elsewhere, Montpellier climbed to fourth thanks to their win in Agen while Racing MÃ©tro picked up valuable points away from home against Bordeaux-BÃ¨gles.
Bayonne 22-12 Castres - Match report here
Perpignan 26-19 Clermont
Agen 9-13 Montpellier
Bordeaux-BÃ¨gles 15-22 Racing MÃ©tro
Stade FranÃ§ais 35-6 Grenoble
Toulon 15-9 Mont-de-Marsan
Toulouse 19-14 Biarritz - Match report here
USA Perpignan 26-19 ASM Clermont Auvergne
Stade AimÃ© Giral, Perpignan
A great result for USAP, who produced one of their best performances if the season to keep their play-off ambitions alive.
Clermont led 12-6 at the end of an intense first half thanks to the boot of Morgan Parra, as they dominated possession but couldn't unlock the Catalan defence.
The second half was a different story however and the hosts took the lead in a barnstorming ten minutes after the break highlighted by a try for lock Romain Taofifenua as the USAP pack rumbled over the line.
Clermont regained the lead around the hour mark when Julien Bardy scored at the back of a rolling maul but the visitors' discipline let them done in the final quarter, allowing James Hook, who finished with 18 points, to kick Perpignan to victory.
Pens: Hook 6
Pens: Parra 4
Yellow card: Sivivatu
Perpignan: 15 Joffrey Michel, 14 Farid Sid, 13 David Marty, 12 Lifeimi Mafi, 11 Adrien Plante, 10 James Hook, 9 Florian Cazenave, 8 Luke Narraway, 7 Bertrand Guiry, 6 Alasdair Strokosch, 5 Romain Taofifenua, 4 Sebastien Vahaamahina, 3 Nicolas Mas, 2 Guilhem Guirado, 1 Sona Taumalolo,
Replacements: 16 Romain Terrain, 17 Sebastien Taofifenua, 18 Robins Tchale watchou, 19 Daniel Leo, 20 David MÃ©lÃ©, 21 Sione Piukala, 22 Richard Haughton, 23 Kisi Pulu
Clermont: 15 Jean Marcellin Buttin, 14 Sitiveni Sivivatu, 13 Regan King, 12 Wesley Fofana, 11 Aurelien Rougerie, 10 Brock James, 9 Morgan Parra, 8 Damien Chouly, 7 Alexandre Lapandry, 6 Gerhard Vosloo, 5 Loic Jacquet, 4 Julien Pierre, 3 Daniel Kotze, 2 Benjamin Kayser, 1 Vincent Debaty.
Replacements: 16 Benoit Cabello, 17 Thomas Domingo, 18 Nathan Hines, 19 Julien Bardy, 20 Ludovic Radosavljevic, 21 David Skrela, 22 Naipolioni Nalaga , 23 Adrien Oleon.
SU Agen 9-13 Montpellier HÃ©rault Rugby
Stade Armandie, Agen
Montpellier were made to work very hard, but got the job done and leapfrogged Grenoble and Castres in the standings as a result.
Despite being reduced to 14 men after the sending off of full-back Ben Seymour for taking FranÃ§ois Trinh-Duc out in the air in the 20th minute, Agen put up a real fight and only trailed 7-6 at half time.
Montpellier should have put the game to bed in the second half but struggled at scrum time and were regularly penalised while on the attack.
Pens: Barnard 3
Rec card: Seymour
Con: Bustos Moyano
Pens: Bustos Moyano 2
Yellow cards: De Marco, van Vuuren
Agen: 15 Ben Seymour, 14 Saimoni Vaka, 13 Vincent Roux, 12 Senio junior Pelesasa, 11 Nafitalai henry Tuitavake, 10 Conrad Barnard, 9 Mathieu Loree, 8 Opeti Fonua, 7 Marc Giraud, 6 Ueleni Fono, 5 Ross Skeate, 4 Lisiate Faaoso, 3 Gert Muller, 2 Jalil Narjissi, 1 Bernard N nomo,
Replacements: 16 Semisi Telefoni, 17 John Schwalger, 18 Esteban Lozada, 19 Remi Vaquin, 20 Alexi Bales, 21 Jean francois Coux, 22 Silvere Tian, 23 Viliamu Afatia
Montpellier: 15 Martin Bustos Moyano, 14 Timoci Nagusa, 13 Thomas Combezou, 12 Shontayne Hape, 11 Yoan Audrin, 10 Francois Trinh-Duc, 9 Julien Tomas, 8 Alex Tulou, 7 Mamuka Gorgodze, 6 Alexandre Bias, 5 Thibaut Privat, 4 Mickael De marco, 3 Maximiliano Bustos, 2 Agustin Creevy, 1 Mikheil Nariashvili.
Replacements: 16 Erasmus Jansen van vuuren, 17 Yvan Watremez, 18 Alikisio Fakate, 19 John Beattie, 20 Benoit Paillaugue, 21 Paul Bosch, 22 Benjamin Thiery, 23 Barry Faamausili.
Union Bordeaux-BÃ¨gles 15-22 Racing MÃ©tro 92
Stade AndrÃ© Moga, BÃ¨gles
Racing-MÃ©tro keep their hopes of the knock-out rugby alive with an invaluable win on the road despite the absence of suspended leaders Dimitri Szarzewski and Fabrice Estebanez.
Bordeaux-BÃ¨gles led 9-6 at half time but conceded 13 unanswered points during the sin binning of captain Mathew Clarkin, with Racing centre Alexandre Dumoulin landing the killer blow just before the hour mark.
A losing bonus point for UBB leaves them level with Agen on the edge of the relegation zone.
Pens: Lopez 5
Yellow card: Clarkin
Red cards: Toetu
For Racing MÃ©tro:
Pens: Wisniewski 4, Machenaud
Yellow cards: Dumoulin, Metz
Bordeaux-BÃ¨gles: 15 Bruce Reihana, 14 Metuisela Talebulamaijaina, 13 Julien Rey, 12 Andrew Mailei, 11 Felix Le bourhis, 10 Camille Lopez, 9 Heini Adams, 8 Justin Purll, 7 Matthew Clarkin, 6 Louis benoit Madaule, 5 Adam Jaulhac, 4 Cameron Treloar, 3 Silviu Florea, 2 Wayne Avei, 1 Laurent Delboulbes,
Replacements: 16 Hikairo Forbes, 17 Jefferson Poirot, 18 Francois Tisseau, 19 Gautier Gibouin, 20 Baptiste Serin, 21 Lachie Munro, 22 Rafael Carballo, 23 Albert Toetu
Racing MÃ©tro:15 Juan Martin Hernandez, 14 Benjamin Fall, 13 Guillaume Bousses, 12 Alexandre Dumoulin, 11 Juan Imhoff, 10 Jonathan Wisniewski, 9 Maxime Machenaud, 8 Jacques Cronje, 7 Bernard Le roux, 6 Camille Gerondeau, 5 Manuel Carizza, 4 Francois Van der Merwe, 3 Luc Ducalcon, 2 Benjamin Noirot, 1 Julien Brugnaut.
Replacements: 16 Thomas Bianchin, 17 Eddy Ben Arous, 18 Jone Qovu, 19 Alvaro Galindo, 20 Henry Chavancy, 21 Olly Barkley, 22 Fabrice Metz, 23 Juan pablo Orlandi.
Stade FranÃ§ais Paris 36-6 FC Grenoble
Stade CharlÃ©ty, Paris
A timely bonus-point win for Stade FranÃ§ais, who remain