Paris - Two-time European Cup winners Wasps on Sunday roared back into contention for a quarter-final place with a bonus point 32-17 win away at ailing French side Castres on Sunday in the European Champions Cup.
Wasps outscored Castres - who have won just four games this season and are bottom of the Top 14 table just two years after being crowned French champions - four tries to two.
Victory takes Wasps onto seven points, a point behind table-topping Pool 2 duo Harlequins and three-time champions Leinster, who play each other later.
Castres, who last reached the knockout stages in 2002 when they were beaten by Munster in the semi-finals, are rooted to the bottom with just one point after three games.
Wasps got off to a dream start as fullback Rob Miller touched down in the fourth minute running onto an excellent grubber kick by Tom Varndell - Andy Goode converted for 7-0.
Castres hit back almost immediately as hooker Mathieu Bonnello went over after the ball was worked out wide to the left and Rory Kockott converted for 7-7.
Ashley Johnson's quick hands set up Wasps Kiwi No8 Nathan Hughes for another try in a breathless few minutes as he brushed off three tackles to go over in the far right hand corner to make it 12-7 after 14 minutes.
Kockott missed the chance to close the gap as he hit the bar with one penalty attempt and then dragged another wide - Goode by contrast slotted one over to extend the English side's lead to 15-7.
The home team, though, were right back in it when centre Remi Lamerat touched down six minutes from half-time - Kockott converted for 15-14.
Castres took the lead for the first time in the match 14 minutes from time as fullback Julien Dumora converted a superb penalty from wide out on the right to go 17-15 up.
However, Wasps regained the lead thanks to another penalty from Goode and the video referee all but assured the English club of victory with 10 minutes remaining.
Instead of awarding a try to Varndell, when he went over in the corner, the official decided that Sitiveni Sivivatu had gone high in the tackle and told referee George Clancy to award a penalty try and give the former All Black a yellow card.
Goode converted for 25-17 while the Castres coach spread his arms in disbelief and stared up at the TV official.
Wasps poured on the misery for the French team adding another try through Sailosi Tagicakibau which Goode converted.