Leinster retained a slender grip on their Heineken Cup title with a bonus-point 33-14 victory over Scarlets at the RDS.

The holders and three-time champions need five points from both of their final two games in Pool 5 to have a chance of securing a best runners-up berth in the quarter-finals and this completed half the job.

Despite conceding an early penalty to Aled Thomas, Leinster quickly seized control of the game and made their intentions clear when Jonathan Sexton ignored the posts to put a penalty into the corner.

It paid immediate dividends as after a ferocious burst of forward pressure, Cian Healy blasted his way over from close range, with Sexton converting for a 7-3 lead.

Liam Williams replied with a fine 40-metre drop goal but the one-way traffic continued as after a driving lineout from close range, Shane Jennings swept off the back of the rolling maul to touch down.

The conversion was missed but just past the half-hour mark the Scarlets scrum was pushed off its own ball in front of their posts and after a series of punishing forward drives, the ball was swept out wide for Luke Fitzgerald to dive over in the corner.

Sexton converted this time although Scarlets got some reward for their stirling efforts throughout the half with a try in added time, Scott Williams lofting out a beautifully weighted cross-kick for Liam Williams to collect in splendid isolation on the wing and touch down.

The conversion was missed but despite conceding three tries, the visitors were still in the game at 19-11 at the break.

Leinster started the second half in even more frenzied fashion and the bonus point came after just three minutes, as Rob Kearney arrived on a perfect line and weaved his way over beneath the posts, with Sexton converting.

Aled Thomas kicked another penalty for the visitors but inevitably the intensity quickly drained out of the game, although Ian Madigan's try off the back of a scrum in the final minute may yet prove crucial if try-count comes into play.

Leinster's thoughts can now turn to repeating the feat at Exeter next weekend, while Scarlets must dwell on a fifth straight defeat in Pool 5.