Wasps scored seven tries to reclaim top spot in Pool 3 with a third straight win following earlier successes against Viadana and Bayonne back in October.
The comprehensive nature of last week's win and the fact that it all but ended Grenoble's own quarter-final hopes would hint at an easy afternoon's work for Dai Young's men, but back rower James Haskell insists that won't be the case at Adams Park.
"French sides on an off day can be terrible and on their day can beat anyone in the world. I think Grenoble this week are going to be a massive threat," said Haskell, who was an Amlin Challenge Cup finalist with Stade Francais in 2012.
"I'm expecting a backlash. From my experience of having played out there I know they're going to come at us and be very physical and we need to be spot on. It'll be a great test for us. They're great natural rugby players and they will be hurting after last week.
"It's important that we don't let it slip. It's too easy to beat them away and then get complacent. We need to be consistent."
Wasps currently head Pool 4 by four points from Bayonne but, with the second-placed side facing struggling Viadana this weekend and with Wasps still having to travel to the Stade Jean-Dauger, victory against Grenoble could be vital to their hopes of heading towards a fourth European trophy.