The hand injury suffered by Benoit Baby has forced the 2006 and 2010 Heineken Cup finalists into the change with Barraque - who celebrated his 21st birthday less than a month ago - partnering the hugely experienced Damien Traille in the midfield with Argentine international Marcelo Bosch on the bench.
Captain and No8 Imanol Harinordoquy proved his recovery from a knee injury by going the full distance last weekend in the Top 14 win against Stade Français Paris, while veteran prop Sylvain Marconnet is on replacement duty for potentially his 88th and final European match before hanging up his boots.
Barraque and Traille will go head-to-head in the centre with Wallaby legend Matt Giteau and Mathieu Bastareaud, with Jonny Wilkinson and Sebastien Tollous-Borde named as the Toulon half back combination.
Welsh prop Eifion Lewis-Roberts and England flanker Steffon Armitage - this week honoured as the Top 14 Players' Player-of-the-Season - both start for the 2010 tournament finalists who are searching for their first piece of silverware for 20 years.
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