The London side were beaten for a second game in a row in the Aviva Premiership last weekend.
The club's director of rugby told Sky Sports News: "We've had a difficult couple of weeks. We've lost the last two matches, so the Heineken Cup has come at a great time for us.
"There is a freshness of the Heineken Cup, playing against teams you know well but don't know intimately. To play Scarlets and then have a trip to Clermont next week will be nice, so there is a real buzz about the group.
"We feel that as a group we have started the season way too slowly, and we want to put that right this weekend."
Quins host Scarlets tomorrow.