Stade Francis Paris coach Fabien Galthie believes Cardiff Blues are in poll position in Pool 3 following his side's defeat at Bristol.
Minus eight front-line internationals, the French champions slipped to their fourth successive Heineken Cup defeat in England and failed to score for the first time in 62 matches in the tournament.
The Blues, who notched a maximum five points against Bristol in the first round and picked up two from their 13-13 draw at Harlequins in round two, now lead the Pool by two points from Stade.
That makes their back-to-back games in the French and Welsh capitals next month critical in the race to reach the quarter-finals.
"I think he Blues have a great chance now because they picked up five points in their first match and then two away in their second. It is going to be difficult for the Harlequins now, having dropped points at home, but it is also going to be hard for us," admitted Galthie.
"The Blues impressed me in their opening two games and they are going to present us with a big challenge in the next two rounds. The most important thing for us now is to keep the spirit of the side high and be positive.
"It is very difficult to play when you are under the kind of pressure that Bristol put on us. We need good weather and a good pitch to play at our best and we aren't at our best at the moment."
Injuries to Italian back row stars Sergio Parisse and Mauro Bergamasco made it an even more miserable afternoon for Galthie. Parisse could be ruled out for six weeks with hiss ankle problem.
However, there is some good news for Stade with Juan-Martin Hernandez due to return in this weekend's French championship match.