Biarritz Olympique are targeting a big away win against English Champions Saracens to put them back in pole position in Pool 5.
The French side are currently a place and two points behind Sunday's opponents with two rounds of action remaining.
Following their game at Vicarage Road, Biarritz host the Ospreys but head coach Patrice Lagisquet is looking for an upset this weekend.
"We are going over there to play rugby and this is a big game for us," he said.
"In the first game against Saracens we were very good and we will have to be the same again if we want to get the victory.
"We want to qualify so we know we have to play well and get the victory."
Inconsistent form has seen Biarritz struggle towards the bottom of the French TOP14 this season but they are turning over a new leaf according to Lagisquet, and that began by beating Agen last weekend
"January is a new start for us, it's a big month," he added.
Vicarage Road could see the return of captain Imanol Harinordoquy from injury. The French back-row has been nursing a knee injury during the past few weeks but is targeting a return against Saracens.