Elliot Daly scored two tries as Wasps kept alive their hopes of progressing to the Champions Cup quarter-finals with a hard-fought 21-3 victory.
Wasps avenged their 49-29 hammering at La Rochelle last weekend but this game at the Ricoh Arena was a far cry from last week's try-scoring extravaganza in France.
The home pack shaded a titanic forward battle as the French failed to come to terms with the murky conditions until the final quarter and could only manage a penalty from Brock James in response to Wasps' three tries.
A late effort from Tom Cruse added to Daly's pair, with Daly converting two and Danny Cipriani one.
Despite this important win, Wasps still have it all to do to qualify for the quarter-finals as they remain in third place in Pool One, three points behind Ulster and five points behind leaders La Rochelle.
Wasps went close to opening the scoring in the sixth minute when Nathan Hughes and Dan Robson both made strong runs before Christian Wade was forced into touch inches from the tryline.
However the home side suffered an early injury blow when Jimmy Gopperth was forced off with a leg injury and was replaced by Kyle Eastmond.
Wasps overcame this setback to score the first try when after some sustained pressure, Daly brushed away a weak tackle from Gabriel Lacroix to score before the wing got up to fire over the touchline conversion.
Another error from Lacroix, this time a deliberate knock-on, presented Daly with a chance to extend the lead but his penalty was off-target so his side just had a 7-0 lead at the end of the first quarter.
Wasps dominated the first half-hour but as the interval approached, their opponents built up their first period of pressure but could not capitalise due to poor handling in the miserable conditions and the forgettable second quarter finished scoreless.
The hapless Lacroix was replaced at half-time by Pierre Boudehent before Wasps missed a good opportunity to score their second try.
A clearance from scrum-half, Alexi Bales, was charged down by James Gaskell and the Wasps lock looked firm favourite to win the race for the touchdown but Bales got back in the nick of time to retrieve his error.
However, the hosts' second try was not delayed for long as Wade stretched the defence down the right flank before the ball was swiftly moved left for Willie Le Roux to send Daly over.
Daly again converted with a splendid kick before La Rochelle replaced Ryan Lamb with James at fly-half.
Daly limped off after 55 minutes before James put the visitors on the scoreboard with an easy penalty, but Cruse's try from a line-out drive, seven minutes from the end, sealed victory.