Dragons' return to Europe's top flight after more than a decade ended in defeat at home to Wasps, after two positive Covid tests cast uncertainty over whether the game would go ahead.

Wasps secured a bonus-point start to their campaign with tries from Tom Cruse, Dan Robson Jack Willis and Thomas Young.

Jonah Holmes crossed for Dragons.

Ashton Hewitt, Lloyd Fairbrother, Aaron Wainwright and Harrison Keddie were due to start for Dragons, but were withdrawn along with replacements Leon Brown and Matthew Screech.

Aaron Jarvis, Holmes and back-row duo Lewis Evans and Taine Basham came into the starting XV.

The late changes gave Dragons a disjointed feel, with problems at the scrum and lineout.

They were reduced to 14 men on 20 minutes when Jarrod Rosser was shown a yellow card for a no-arms tackle on his opposite number Zach Kibirige, who had been tearing down the touchline.

Last season's English Premiership finalists took advantage of a gaping hole in the defence moments later with hooker Cruse running in a simple try.

Dragons responded through a Sam Davies penalty after a typical Taine Basham turnover, but a lack of concentration soon after led to Wasps' second score.

Full-back Lima Sopoaga began the move from his own half before offloading to Josh Bassett, who threw a dummy before moving the ball back inside to the supporting Robson to cross under the posts.

Experienced Kiwi Jimmy Gopperth added the extras.

Wasps were made to pay for their own indiscipline just after the break with Sopoaga sent to the sin bin for a no-arms tackle on Josh Lewis.

Dragons chipped away at the defence and a breakthrough eventually came when the ball was shipped across field to Jamie Roberts on the wing, who fed inside for Holmes to score.

No sooner were Wasps back to a full complement, than referee Romain Poite finally lost patience with the Dragons front row and sent Jarvis to the bin, although Gopperth was unable to convert the resulting penalty.

Wasps appeared to take their foot of the gas with momentum shifting to the home side but they were unable to convert pressure into points.

After weathering the storm, there were two quick scores from back rowers Willis and Wales international Young.

Willis continued a sparkling season by powering over after a breakaway from a driving maul, while Young ran a good angle to put the game beyond doubt and secure a vital bonus point.

Dragons director of rugby Dean Ryan told BBC Sport Wales:

"We don't spend all this time preparing to then change eight players on a Friday night/Saturday morning.

"That's obviously a disruption but it is part of the landscape.

"We were 100% clear on testing on Tuesday... but we ended up with two symptomatic players on Friday which is probably the worst time for us so we had to test.

"It's a difficult 24 hours then because you've got to react to it and it's the worst time to look at close contacts because obviously we trained as a squad on Thursday and Friday.

"I'm always proud of the Dragons. What we're playing in this environment is to keep adding to our lessons and I think we had a moment, maybe two, where we could have won the game."

Dragons: J Lewis; J Rosser, N Tompkins, J Roberts, J Holmes; S Davies, R Williams (capt); B Harris, R Hibbard, A Jarvis, B Carter, J Maksymiw, L Evans, T Basham, O Griffiths.

Replacements: E Dee, J Reynolds, L Yendle, J Davies, L Greggains, T Knoyle, J Dixon, O Jenkins.

Wasps: L Sopoaga; Z Kibirige, P Odogwu, J Gopperth, J Bassett; C Atkinson, D Robson; T West, T Cruse, K Brookes, J Launchbury (capt), W Rowlands, J Willis, T Young, A Barbeary.

Replacements: G Oghre, Zhvania, J Toomaga-Allen, T Cardall, B Morris, W Porter, M Le Bourgeois, M Minozzi.

Referee: Romain Poite (France)

Assistant referees: Dan Jones (Wales), Gwyn Morris (Wales)

TMO: Nigel Owens (Wales)