Joe Marler, Charlie Walker and Danny Care crashed over in the first-half before Jack Clifford, Mark Lambert, Marland Yarde and George Lowe wrapped up the 47-19 victory – but it counted for nothing after Wasps fought back to draw against Leinster.

Wasps claimed more match day points than Conor O’Shea’s side in their two head-to-head meetings which handed them second spot in Pool 2, leaving them in an agonising third place with 18 points.

Harlequins were gifted some early field position when Castres centre Romain Cabannes called a mark under his posts and attempted a cheeky tap and go. Marcel Garvey could not collect his ambitious ball and O’Shea’s side went on the attack. 

They made them pay for the mistake moments later. Castres were caught offside and Nick Evans sent a statement of intent by going for the corner. They shunted the Frenchmen back to claim the first of the four scores they required to keep themselves afloat in the Champions Cup.

But Quins returned the favour five minutes later when England full-back Mike Brown fumbled a pass behind his own try-line, allowing Castres to put the drive on from five-metres out. The scrum turned and buckled before scrum-half Antione Dupont scurried from the base and took on Brown, who let the nippy number nine get outside him for the levelling score. 

But it swung back the Londoners way before the thirty-minute mark. They marched back downfield and won a penalty, which Danny Care took quickly. 

They built more pressure and it eventually told when wing Walker popped up in midfield and side-stepped through the covering defence to score.  The match looked there for the taking for the English side, but some more lax defending allowed Piula Faasalele to set Romain Cabannes free for a run to the line, Julien Dumora converted to draw the sides level once more.

Thomas Cambezou saw yellow as the clock went dead for half-time after he pulled back George Lowe, and Harlequins got their third before the break as Care sniped and scored from close range. They started the second-half as they ended the first and bagged the crucial bonus-point within nine minutes. 

Brown sent a well measured grubber kick through the defensive line and Walker raced onto bouncing ball. 
He then found Clifford running a well timed supporting line, and Clifford crashed over in the snow. 
Remi Grosso was the next Castres man to be sent to the sin-bin and Quins capitalise again when Lambert latched onto Nick Easter’s pop pass to score.

Nick Evans jinked through the line moments later and fed Yarde, who raced 30 metres to wrap-up the result in France. Castres showed they were not dead and buried after 65 minutes when they chose to scrummage a penalty.

They powered through the Quins pack and Johnny Beattie was on hand to fall on the ball at the back of the scrum to score to give his a third try. Lowe boosted Quins points difference with the seventh converted try, but it was not enough as they moved level on 18 points with Wasps and crashed out of the competition.