Oyonnax maintained their fine early-season form when they beat Toulon 25-22 at Stade Charles-Mathon in Oyonnax on Saturday.
Benjamin Urdapilleta was the newly promoted team's hero after he secured victory with a drop-goal in the game's closing stages.
Oyonnax made a perfect start when Florian Denos scored their only try after just three minutes which Urdapilleta converted.
The hosts' only other points came through penalties from Urdapilleta and Valentin Ursache but it was the boot of Toulon fly-half Jonny Wilkinson which kept the visitors in the match.
Wilkinson succeeded with four penalties and also converted a Delon Armitage try, shortly before half-time to give Toulon a 19-13 lead at the break.
Oyonnax struck back with a drop-goal from Conrad Barnard, shortly after the restart, and Urdapilleta added further three-pointers in the 54th and 59th minutes which gave last season's Pro D2 winners a 22-19 lead.
Wilkinson drew Toulon level with another penalty two minutes later before Urdapilleta produced his injury-time heroics to secure his side the shock result of the Top 14 season so far.
Pens: Urdapilleta 3, Ursache
Drops: Barnard, Urdapilleta
Tries: D Armitage
Oyonnax: 15 Florian Denos, 14 Silvere Tian, 13 Pierre Aguillon, 12 Hemani Paea, 11 Jonathan Bousquet, 10 Benjamin Urdapilleta, 9 Agustin Figuerola, 8 Viliami Maafu, 7 Valentin Ursache, 6 Christophe Andre, 5 Damian Browne, 4 Thibault Lassalle, 3 Marc Clerc, 2 Jody Jenneker, 1 Lukas Rapant.
Replacements: 16 Neil Clark, 17 Clement Baiocco, 18 Damien Lagrange, 19 Scott Newlands, 20 Fabien Cibray, 21 Conrad Barnard, 22 Roimata Pune, 23 Antoine Tichit.
Toulon: 15 Delon Armitage, 14 Drew Mitchell, 13 Mathieu Bastareaud, 12 Matt Giteau, 11 David Smith, 10 Jonny Wilkinson, 9 Michael Claassens, 8 Chris Masoe, 7 Danie Rossouw, 6 Virgile Bruni, 5 Ali Williams, 4 Bakkies Botha, 3 Carl Hayman, 2 Benjamin Noirot, 1 Andrew Sheridan.
Replacements: 16 Jean Charles Orioli, 17 Xavier Chiocci, 18 Konstantine Mikautadze, 19 Joe van Niekerk, 20 Maxime Mermoz, 21 Josua Tuisova, 22 Alexis Palisson, 23 Martin Castrogiovanni.
Referee: Romain Poite