Former All Blacks prop Kees Meeuws accepts it will be "a tough ask" for his Castres team to sink European Cup Pool One leaders Sale Sharks at Edgeley Park on Friday night.
Sale's 20-16 victory in Castres last Friday strengthened their quarter-final chances, and the Guinness Premiership top dogs will undoubtedly target a winning bonus point against a French outfit whose previous away European Cup trip this term saw them crash 42-16 to Munster.
Castres coach Laurent Seinge has also made eight changes for the Stockport trip, with Meeuws not included and his fellow New Zealand prop Carl Hoeft among the replacements.
"It's obviously going to be a tough ask for us to win at Sale, but if we keep it together and have confidence, we should be able to win," insisted Meeuws.
"We played the right game-plan in the home leg, and there are just a few areas we have to tighten up on and that should see us through."
Edinburgh coach Todd Blackadder has retained the side beaten 20-13 by tournament favourites and Pool Six leaders Toulouse at Murrayfield last weekend for the return in southern France.
And Blackadder is optimistic Edinburgh can give a strong account of themselves as they look to keep themselves in quarter-final contention, with their chances boosted by Toulouse half-backs Frederic Michalak and Jean-Baptiste Elissalde both battling injuries.
"I feel this is a team that can go to Toulouse and win," he said. "There were positives to come out of the game last weekend - our defence was very good, and we were strong in attack.
"It is frustrating because we have a team that is capable of beating the top sides in Europe, but we will go to Toulouse with the aim of asking some serious questions."
In the second-tier European Challenge Cup, Pool One leaders Northampton face a tricky assignment away to Narbonne on Friday, with their cause hindered by injuries that have sidelined fly-half Carlos Spencer (hand), wing Sean Lamont (ankle) and centre Rhodri Davies (groin).