Prop Fabio Staibano quickly got a second for the 2003 tournament champions before powerhouse No8 Billy Vunipola muscled his way over for their third.

Flanker Owen Evans gave the Dragons a lift with their second try before the break but, with former Wales outside-half Nicky Robinson on song with the boot, Wasps kept a healthy advantage.

Scrum-half Joe Simpson got the try that clinched the bonus point for Wasps with 20 minutes remaining. It also provided them with a 20-point lead and saw them match Bayonne's five-point haul at the top of the group.

But the Dragons kept plugging away and teenager Jack Dixon got their second try to bring greater respectability to the final scoreline.