That is despite the fact Pool Three has been blown wide open by Sale's 12-6 victory over the French champions in round four which keeps alive the qualification hopes of the English champions.
.. "We did not play as well as we can against Sale," said de Villiers, whose side know exactly what they will face in Swansea in the next round after losing there last season.
"It is important for us to represent France and it seems to be difficult for French clubs in this year's European Cup. It's important for Stade and Biarritz to try to get other teams to come with them but it is going to be tough.
"The game at the Ospreys will be a deciding match for the quarter-finals and they are playing very good rugby as well.
"We know what we are letting ourselves in for, we know they are a good team with lots of internationals - strong up front and quite complete out wide.
"We would like a home quarter-final, but a place in the last eight will be a tough matter and we have to try to get there first."