Toulon qualified for the Top 14 semi-finals after a tense, come-from-behind 17-13 play-off win over Racing Metro on Saturday.
Toulon will face Clermont in their June 3 semi, with Castres, who beat Montpellier 31-15 on Friday, up against Toulouse 24 hours earlier.
Toulon were made to work for this win, Jonny Wilkinson's side trailing 13-3 at half-time following a try by Benjamin Fall and eight points from the boot of Sebastien Descons and Francois Steyn.
Toulon's only points at the break were one successful penalty from Wilkinson from four attempts.
Australian Matt Giteau took over from the misfiring England star in the second period to add the first six points after the break.
After the hour, Toulon were back in the game at 13-9, and they then took the lead for the first time when flanker Steffon Armitage touched down with Giteau adding a late penalty to see Toulon home.
Toulon: 15 Luke Rooney, 14 Benjamin Lapeyre, 13 Mathieu Bastareaud, 12 Matt Giteau, 11 David Smith, 10 Jonny Wilkinson, 9 Sebastien Tillous-Borde, 8 Juan Martin Fernandez Lobbe, 7 Steffon Armitage, 6 Joe van Niekerk, 5 Simon Shaw, 4 Bakkies Botha, 3 Davit Kubriashvili, 2 Mickael Ivaldi, 1 Eifion Roberts.
Replacements: 16 Jean Charles Orioli, 17 Laurent Emmanuelli, 18 Christophe Samson, 19 Pierrick Gunther, 20 Christian Loamanu, 21 Geoffroy Messina, 22 Fabien Cibray, 23 Levan Chilachava.
Racing: 15 Frans Steyn, 14 Benjamin Fall, 13 Henry Chavancy, 12 Fabrice Estebanez, 11 Juan Imhoff, 10 Juan Martin Hernandez, 9 Sebastien Descons, 8 Jacques Cronje, 7 Antoine Battut, 6 Johnny Leo'o, 5 Francois Carl Van der Merwe, 4 Lionel Nallet, 3 Mikaele Tuugahala, 2 Benjamin Noirot, 1 Julien Brugnaut.
Replacements: 16 Thomas Bianchin, 17 Eddy Ben Arous, 18 Karim Ghezal, 19 Alvaro Galindo, 20 Mathieu Loree, 21 Jonathan Wisniewski, 22 Virimi Vakatawa, 23 Benjamin Salemane Sa.