Harlequins bounced back from the shock of conceding a converted try in the opening 35 seconds to easily book their passage into the fifth round of the Powergen Challenge Cup with a 48-6 win over Toulouse.
They ran in nine tries without conceding a further point and never really looked like losing to the French side.
David Myles took advantage of a Nick Bradley-Qalilawa knock-on from the kick-off to score between the posts and James Wynne converted the try to give Toulouse their lead.
Tony Clubb scored the equalising try after 16 minutes, catching a diagonal bomb from Luke Dorn and Matt Gafa added the extras.
When Toulouse lost the ball on halfway, after 24 minutes, Harlequins struck again - Mark McLinden and Dorn combining to send over Tyrone Smith to give London the lead. The last 38 points came in the final 28 minutes of the game.
Gafa scored from a Luke Dorn pass after Toulouse had been penalised in possession inside their own 10-metre line.
Three minutes later Dorn charged down a Myles kick and went 90m for a spectacular try. He then ran on to a diagonal kick from McLinden to give Quins a 20-point cushion.
After 67 minutes Thomas Leuluai survived a decapitation attempt as he ducked and weaved his way to score from close range.
Seven minutes later Leuluai and Smith combined to give Bradley-Qalilawa a try in the corner - after scoring 20 last season, it was his first of this term.
The last two tries give great hope to London rugby League because it was a local boy, Clubb, who scored both to complete his hat-trick.
The first came after a break from Leuluai which was continued by Lee Hopkins and he scored in the corner.
Toulouse were convinced there had been both a forward pass and a foot in touch by Clubb before the ball was put down but the protests were waved away.
The last move of the game saw Gafa gouge a hole in the Toulouse line and Clubb sprinted 35 metres between two hesitant defenders before going behind the posts to touch down. Gafa�s conversion was his sixth successful kick from nine attempts.
Harlequins RL (10) 48 Toulouse (6) 6 Tries: Dorn 2, Leuluai, Smith, Bradley-Qalilawa, Clubb 3, Gafa Myles Goals: Gafa 6 J Wynne
Harlequins RL: McLinden, Clubb, Smith, Gafa, Bradley-Qalilawa, Dorn, Leuluai, Heckenberg, Randall, Tookey, Haumono, Hopkins, Williams. Replacements: Mills, McCarthy-Scarsbrook, Budworth, Weisner.
Toulouse: Clayton, Olieu, Lima, Houles, Viala, Myles, J. Wynne, Prizzon, Gay, McDonald, Vincent, Raguin, Delpoux. Replacements: Arlas, Frayssinet, Howell, Amigas.
Referee: P Bentham (Warrington)