As so often between these sides, it came down to a battle of the kickers with Jonathan Sexton kicking three penalties to his long-term adversary Ronan O'Gara's one in the first half.
After O'Gara levelled the scores with a pair of penalties after the break, Sexton nudged Leinster back in front on 60 minutes before replacements Fergus McFadden and Ian Madigan wrapped up the victory and denied Munster the consolation of a bonus point in the process.
The visitors so nearly made the perfect start at Thomond Park when Sexton's clever chip over the top found a flying Rob Kearney, but the full-back couldn't quite gather the ball as he raced towards the corner.
While Munster won the nudge in the first scrum, Mike Ross - who was part of the Irish front-row that endured a torrid afternoon at Twickenham - gained a measure of revenge by forcing a Leinster penalty after ten minutes which Sexton converted.
The scrum was shaping up to be a titanic struggle as Ross was this time penalised when Marcus Horan forced him to the turf but O'Gara's kick came off the post.
The Munster fly-half was also off target with a drop goal but with a penalty coming in front of the posts after Sean Cronin was pinged for going in off his feet he made no mistake to get the home team on the board.
Parity was shortlived with Sexton kicking two penalties in quick succession with Horan, the guilty party at the scrum for the second offence.
Munster finished the half deep in Leinster territory but could force neither a defensive slip nor an indiscretion that left them six points adrift at the break.
The scrum, the shaping force of the first half, soon came to the fore early in the second when referee Nigel Owens lost patience with the repeated collapses and dispatched both Ross and Horan to the sin-bin.
Munster seemed to benefit most from the new 14-a-side format with O'Gara soon slotting his second penalty on 47 minutes although he missed another three pointer two minutes later.
But when Kiwi World Cup winner Brad Thorn was adjudged to have made a high tackle on Felix Jones, O'Gara levelled the scores from distance.
Leinster remained the greater threat with ball in hand and both Isa Nacewa and Kearney tested the home defence with runs before Sexton burst into the 22 before being scragged by Mick O'Driscoll.
The lock though was pinged for not releasing and Sexton kicked them back ahead although that prove to be his last act as he was replaced by Madigan, who has deputised superbly for Sexton in the RaboDirect PRO12 this season.
Leinster's main threat still came in the form of livewire wing Nacewa who twice sliced his way through the Munster defence only to find support lacking at the crucial moment.
The visitors remained in the ascendancy however and McFadden booted them six points in front with ten minutes to go after another Munster offence at the scrum.
And the win was wrapped up when, following another Nacewa break, Madigan found the space to execute a drop goal in front of the posts that all but secures Leinster's place in the RaboDirect PRO12 semi-finals.
|Munster Rugby Score Card|
|Leinster Rugby Score Card|