Joe Schmidt’s side went about securing the bonus point in a roundabout way, with Fergus McFadden and Ian Madigan crossing in the closing stages after early efforts from Shane Jennings and Isa Nacewa had them 14-0 ahead.

Cardiff rallied impressively in the third quarter, grabbing tries through Bradley Davies and Richie Rees, and a penalty from Dan Parks edged the Welsh region in front at 23-20.

But McFadden’s try helped Leinster reassume control and it was fitting that young out-half Madigan scurried over for the clinching score.

Jonathan Sexton missed out on his first appearance of the season for Leinster when injuring himself in the warm-up, so academy player Madigan stepped in at number 10 for only his second start for the province.

Cardiff travelled on the back of an encouraging bonus-point victory over Edinburgh last weekend, and gave competitive debuts to prop Tom Davies and New Zealand flanker Michael Paterson.

The game was only four minutes old when Isaac Boss managed to spring through a gap between Deiniol Jones and Bradley Davies, and feed the supporting Jennings for the opening try which man-of-the-match Nacewa converted.

Cardiff encountered scrum problems through the first half, so much so that newcomer Davies had to be replaced on the stroke of half-time.

They fell further behind when slick hands from Richardt Strauss and Luke Fitzgerald gave Nacewa enough space to skip by Chris Czekaj for a try he converted himself.

Parks knocked over two successive penalties to close the gap, with Casey Laulala beginning to cause problems for the Leinster defence. But the hosts tightened their grip on proceedings, moving 20-6 clear at the break courtesy of a penalty brace from Nacewa.

The same player put in a try-saving tackle on Richard Mustoe as Cardiff began the second half with intent. Scrum-half Rees had sparked a superb counter attack out of the 22, and the Blues’ new-found adventure was soon rewarded. Parks punted a penalty to touch, and lock Davies muscled his way over off the next phase.

Parks added the extras and after Leinster failed to convert a couple of promising attacking situations, the Blues squared the game at 20-20 thanks to a terrific team try.

Laulala’s long pass set up an overlap on the right and a couple of well-timed deliveries from Davies and Mustoe sent Xavier Rush charging into the 22. The Cardiff skipper’s brilliant offload out of the tackle then put Rees in behind the posts and Parks comfortably converted.

The Scotland international tagged on a penalty for good measure and suddenly Leinster were behind. But Schmidt’s men were up for the challenge and they bounced back to deservedly take the spoils.

Replacement prop Cian Healy drew two defenders on a barge through the middle to tee up McFadden for a sprint in under the posts.

Nacewa converted and in the final minute, took his personal tally to 19 points as he topped off Madigan’s fine snipe from outside the 22.