The Irish side completely dominated the set piece battle at scrum time while Jonny Sexton won his personal fly half duel with Rhys Priestland, putting his forwards on the front foot with his educated right boot and kicking 15 points for the victors.

Having suffered a heavy defeat in their opening pool match against Clermont Auvergne last weekend, the Scarlets were eager to replicate their RaboDirect Pro12 victory over Leinster earlier in the season but it was the visitors who got off to a flying start.

Sexton banged over his first penalty inside two minutes before sending over an inch-perfect cross-field kick towards George North's wing. The big Welshman was always struggling to cover the danger and when Isa Nacewa lept like a salmon to clutch the ball high above North's head, the Fijian forced his way over for the first try of the match.

Despite dominating the first half where the Scarlets were blown away at the breakdown, Leinster only had another Sexton penalty to their name as they went into the break 11-0 up.

Sexton and Rhys Priestland exchanged penalties early in the second half, before centre Gareth Maule showed one of the few touches of class on display for the Scarlets, when he rounded Brian O'Driscoll, before evading the despairing midfielder's tackle to score in the right-hand corner.

A further six points through Sexton's boot stretched Leinster's lead to double figures. A mis-firing Scarlets were given a glimpse of hope late on when full back Ian Madigan took out his opposite number Liam Williams mid-air.

Priestland managed to reduce the arrears with a short range penalty to get the Scarlets back within range but despite finishing with an extra man, the home side were unable to record their opening win of the cup campaign while Leinster were able to celebrate their 17th successive victory in the tournament and coach Joe Schmidt's 17th win from 19 Heineken Cup games.