Toulon held off a spirited comeback from Pau to win 21-17 at the Stade Felix Mayol on Sunday thanks to two tries from James O'Connor.
The former Australia international and lock Konstantin Mikautadze ended up on the scoresheet for the European champions.
However a superb solo try from Conrad Smith and a late penalty try meant that Pau returned home with a losing bonus point.
Colin Slade opened the scoring with a penalty in the second minute for Pau, matched by his former Crusaders' team-mate Tom Taylor of Toulon in a low-scoring first quarter.
O'Connor was finally put into space to run in down the touchline for Toulon's first try on 25 minutes, with another Taylor penalty putting Toulon ahead 11-3 at half-time after they went down to 14 men when Cooper was sent to the sin-bin.
A second try for O'Connor was then matched by Smith, the All Blacks veteran dummying his way past Ma'a Nonu before fending and stepping his way to the line for an impressive score.
More drama was to follow as Toulon replacement hooker Anthony Etrillard saw yellow and Pau were awarded a penalty try to set up a tense finish.
However the hosts clung on, surviving an impressive fightback from Pau as Toulon move back into the top four.
Tries: O'Connor, Mikautadze
Pens: Taylor 2
Yellow Cards: Cooper, Etrillard
Tries: Smith, Penalty Try
Cons: Slade 2
Yellow Card: Jacquot
Toulon: 15 Tom Taylor, 14 James O'Connor, 13 Maxime Mermoz, 12 Ma'a Nonu, 11 Drew Mitchell, 10 Quade Cooper, 9 Sébastien Tillous-Borde, 8 Steffon Armitage, 7 Juan Martín Fernández Lobbe, 6 Mamuka Gorgodze, 5 Konstantin Mikautadze, 4 Jocelino Suta, 3 Levin Chilachava, 2 Guihelm Guirado, 1 Xavier Chiocci
Replacements: 16 Anthony Etrillard, 17 Alexandre Menini, 18 Thibault Lasalle, 19 Charles Ollivon, 20 Mathieu Bastareaud, 21 Bryan Habana, 22 Eric Escande, 23 Matt Stevens
Pau: 15 Mathieu Acebes, 14 Sireli Bobo, 13 Conrad Smith, 12 Jale Vatubua, 11 Watisoni Votu, 10 Colin Slade, 9 Thibault Daubagna, 8 James Coughlan, 7 Paddy Butler, 6 Sean Dougall, 5 Daniel Ramsay, 4 Julien Pierre, 3 Chris King, 2 Quentin Lespiaucq, 1 Julien Jacquot
Replacements: 16 Thomas Bianchin, 17 Jérémy Hurou, 18 Claude Dry, 19 Jovili Domolailai, 20 Thierry Lacrampe, 21 Brandon Fajardo, 22 Julien Fumat, 23 Giorgi Natsharashvili
Referee: Cyril Lafon