They scored first-half tries from number eight Jack Cowan, who got two, before scrum-half Jamison Gibson-Park, hooker Richard Strauss and his replacement James Tracy, replacement Hayden Triggs and two from scrum-half sub Luke McGrath put the Irishman home and dry.

Fly-half Ross Byrne kicked seven conversions against Dragons tries from wing Adam Hughes, lock Matthew Screech and one at the end from replacement scrum-half Sarel Pretorius. Fly-half Dorian Jones booted two conversions and a penalty.

The Dragons got the first points on the board when Leinster were penalised at a scrum in front of their posts and Jones popped over the three points six minutes into the game.

But that was the nearest the home side came to the Leinster line for the next half hour.

They spent a long time defending after Leinster went ahead through a spectacular try.

Full-back Joey Carbery found space near his own 22 and raced through a gap and up field.

The Dragons defenders were scattered as Conan arrived on his colleague's shoulder to take the pass and run in from 22 metres.

Leinster put the squeeze on the Dragons again, this time building the pressure near their line until Conan found a gap to the right of the posts and drove over to give Byrne a simple conversion.

Just seconds after the restart, Leinster went further in front when Gibson-Park saw space and ran over for an easy converted try.

However, the Dragons produced a swift response as a lovely move along the back line near the opposition line saw Hughes dive in at the corner and Jones land a thumping touchline conversion.

From then on, though, Leinster hammered the Dragons as the Welshmen weakened.

Strauss rumbled over from a few metres for the bonus point touchdown before Screech got another for the home side.

But it was one way traffic after that as Trigg and two from McGrath put Leinster over the half century.

A final try by Pretorious was a mere consolation for the Dragons.