Matt Giteau will steer toulon from flyhalf as they vie to make the Top 14 final this weekend.
Giteau has been named at 10 for the side, the only Wallabies representative in the 23 for the French powerhouse.
Toulon takes on Montpellier, with capped Wallabies back Jesse Mogg starting on the left wing for the Jake White-coached team.
Scrumhalf Nic White will come off the bench for Montpellier in the match.
Montpellier and Toulon have split their Top 14 encounters this year, with this their most significant clash of the season.
Mogg's side already has some silverware, having clinched the European Challenge Cup this season.
The winner will take on Racing 92, after Dan Carter delivered another match-winning moment in his decorated career.
Carter slotted a conversion in extra-time to seal a 34-33 win for Racing, sending them into the final over Clermont, the team with the best record this year.
The two sides had been tied 27-27 at the end of normal time with Clermont then nudging ahead 33-27 thanks to a long-range penalty from Scott Spedding and a monster drop goal by Brock James.
But Clermont self-destructed when Georgian flanker Viktor Kolelishvili was yellow carded for a dangerous tackle on Racing prop Luc Ducalcon with seven minutes left.
Argentine winger Juan Imhoff then scored a breakaway try for Racing with three minutes of the 20-minute extra-time period to go and World Cup winner Carter showed nerves of steel to slot over the crucial conversion.
Fritz Lee and Wesley Fofana had scored tries for Clermont in normal time with Johan Goosen and Joe Rokocoko crossing for Racing.
Toulon face Montpellier in the second semi-final, also at Rennes, on Saturday with Racing awaiting the winners in the final to be played at Barcelona's Nou Camp stadium on June 25.
"It's a great satisfaction after a season which has already been very, very long," said Racing coach Laurent Labit whose side will be playing in a first final in 26 years.
"But we can't say it was magnificent as we always want more. We can't rest as there is one more thing to do."
Clermont coach Franck Azema blasted the officiating.
"It's cruel. I don't understand the video decisions -- three of them went against us. I am disappointed and angry," he said.
Camille Lopez popped over a fourth-minute drop goal for Clermont before Carter levelled with a penalty having earlier seen his first attempt come off the upright.
Clermont scrum-half Morgan Parra then saw his first penalty also hit the post before the game sprung into life after 20 minutes.
French international centre Fofana burst through three tackles to score what would have been the first try of the semi-final. But his impressive slalom was ruled out for a forward pass.
Racing, who had defeated Clermont twice in the regular season, then stretched to a 16-6 lead.
Carter hit two more penalties before Johan Goosen pounced on a loose ball to score his seventh try of the season. Carter added the extras.
Clermont cut the deficit to five points at the break with a try on the stroke of half-time.
Spedding had just booted a huge penalty from the halfway line before he then kicked for touch in the corner.
Clermont unleashed a mighty push from the ensuing line-out with Lee the man on the bottom of the pile.
The league leaders were 17-16 ahead early in the second-half before veteran All Blacks winger Rokocoko shrugged off his 32 years to sprint 25 metres to touch down for Racing.
Carter hit the conversion for 24-17 before Lopex cut the lead back to 24-20.
All Blacks legend Carter then hit his fifth successful kick of the semi-final to restore Racing's seven-point lead.
However, Fofana scored his team's second try on the hour mark which was converted by Lopez, sending the match into extra-time.