Perpignan picked up a bonus-point win as they ran in four tries past Montpellier in a 28-16 victory on Friday.
Dewaldt Duvenage, Justin Purll, Sofiane Guitoune and Romain Taofifenua all crossed for the hosts in a match watched by France coach Philippe Saint-André.
Montpellier desperately hunted a losing bonus point late on following Timoci Nagusa's 74th minute try, but it came all too late for last season's Heineken Cup quarter-finalists.
James Hook opened the scoring in the third-minute with a penalty, after signing an extension with Perpignan earlier in the week.
The opening try for Duvenage shortly followed, the South African scrum-half evading tacklers to touch down after confirmation from the TMO.
Purll was in on the action only two minutes later, driving over Francois Trinh-Duc to score after good work from Wandile Mjekevu, as USAP went 15-0 up after ten minutes.
Benoit Paillaugue added a penalty for Montpellier but new France squad member Sofiane Guitoune was on hand for the hosts' third try, as Perpignan put Montpellier at arm's length early on, USAP leading 20-6 at half-time.
Paillaugue's third penalty after the break narrowed the gap until second row Taofifenua was found out on the wing - powering over the last defender to wrap up the bonus point win for his team.
Nagusa's score would come late on and Montpellier did throw everything at Perpignan to try and take the losing bonus point, but it wasn't to be.
Tries: Duvenage, Purll, Guitoune, Taofifenua
Pens: Hook 2
Pens: Paillaugue 3
Perpignan: 15 James Hook , 14 Wandile Mjekevu, 13 Lifeimi Mafi, 12 Sione Piukala, 11 Sofiane Guitoune, 10 Camille Lopez, 9 Dewaldt Duvenage, 8 Luke Narraway, 7 Jean Pierre Perez, 6 Justin Purll, 5 Romain Taofifenua, 4 Sebastien Vahaamahina, 3 Giorge Jgenti, 2 Guilhem Guirado, 1 Sona Taumalolo.
Replacements: 16 Romain Terrain, 17 Sebastien Taofifenua, 18 Daniel Leo, 19 Karl Chateau, 20 Nicolas Durand, 21 David Marty, 22 Joffrey Michel, 23 Paulica Ion.
Montpellier: 15 Benoit Sicart, 14 Lucas Dupont, 13 Thomas Combezou, 12 Wynand Olivier, 11 Yohann Artru, 10 Francois Trinh-Duc, 9 Benoit Paillaugue, 8 Johnnie Beattie, 7 Alexandre Bias (capt), 6 Alex Tulou, 5 Thibaut Privat, 4 Robins Tchale-Watchou, 3 Nicolas Mas, 2 Charles Géli, 1 Yvan Watremez.
Replacements: 16 Mickael Ivaldi, 17 Na'ama Leleimalefaga, 18 Mickael De Marco, 19 Kélian Galletier, 20 Jonathan Pélissié, 21 Anthony Tuitavaké, 22 Timoci Nagusa, 23 Maximiliano Bustos.
Referee: Christophe Berdos
Assistant referees: Tual Trainini, Thierry Laurent Grand
Television match official: Jean-Luc Pellaprat