Argentinian winger Martin Bustos Moyano scored 19 points for Bayonne as they saw off Montpellier 24-19 at the Stade Jean Dauger.
The Basque club achieved victory after an eventful week in which star scrum-half Mike Phillips had been suspended for an off-field incident.
The two players with Phillips, Stephen Brett and Dwayne Haare, were both involved in the matchday squad.
Bustos Moyano may have been successful going for goal with a conversion and five penalties, but it was a miss early in the first half that set Bayonne on their way.
His penalty attempt ricocheted back off the left upright and was reacted to by Santiago Fernandez, making his first start for the club. The resulting passage of play ended with former All Black centre Joe Rokocoko burrowing his way over for the first try and a 7-3 lead.
Bustos Moyano's long-range penalty followed to enhance the advantage until Montpellier levelled the scores - young fly-half Enzo Selponi brilliantly crossing for a try in only his second start, with Benoit Paillaugue converting.
The Argentinian's second penalty put Bayonne back in the lead before he extended it with a try; Brett intercepting a pass from Selponi before releasing Bustos Moyano for Bayonne's second score on the 37th minute for an 18-10 scoreline.
Bustos Moyano and Paillaugue traded penalties but it was the Montpellier scrum-half's next two strikes that gradually drew the visitors closer to Bayonne's lead.
Paillaugue's penalty in the 68th minute had the score at 21-19, before a key scrum from Bayonne earned Bustos Moyano another penalty attempt to give the hosts enough breathing space with a five-point lead.
Replacement Anthony TuitavakÃ© was sin-binned for Montpellier as they frantically chased the win, but Bayonne clung on to end a turbulent few days on a high and move out of the relegation zone in the Top 14.
Tries: Rokocoko, Bustos Moyano
Con: Bustos Moyano
Pens: Bustos Moyano 5
Pens: Paillaugue 4
Yellow Card: TuitavakÃ©
Bayonne: 15 Scott Spedding, 14 Martin Bustos-Moyano, 13 Joe Rokocoko, 12 Santiago Fernandez, 11 Marvin O'Connor, 10 Stephen Brett, 9 Mathieu BÃ©lie, 8 Opeti Fonua, 7 Jean-Jo Marmouyet, 6 Mark Chisholm (c), 5 Lisiate Fa'aoso, 4 Dewald Senekal, 3 Gert Muller, 2 David Roumieu, 1 JC Van Rensburg.
Replacements: 16 Gregory Arganese, 17 Aretz Iguiniz, 18 Dwayne Haare, 19 Jean Monribot, 20 Christopher Loustallot, 21 Bastien Fuster, 22 Sam Gerber, 23 Nemiah Tialata.
Montpellier: 15 Benoit Sicart, 14 Timoci Nagusa, 13 Thomas Combezou, 12 Hamish Gard, 11 Yoan Audrin, 10 Enzo Selponi, 9 Benoit Paillaugue, 8 KÃ©lian Galletier, 7 Mamuka Gorgodze, 6 Alexandre Bias, 5 Robins TchalÃ©-Watchou, 4 Jim Hamilton, 3 Nicolas Mas, 2 MickaÃ«l Ivaldi, 1 Misha Nariashvili.
Replacements: 16 Charles Geli, 17 Maximiliano Bustos, 18 Thibaut Privat, 19 Fred Quercy, 20 Jonathan PÃ©lissiÃ©, 21 FranÃ§ois Trinh-Duc, 22 Anthony TuitavakÃ©, 23 Na'ama Leleimalefaga.
Referee: Pascal Gauzere