Leinster (3) 16
Try: Kearney Cons: Sexton Pens: Sexton 3
Munster (3) 3
Pen: O'Gara Drop-goal: O'Gara
Cian Healy (centre) get support from Malcolm O'Kelly as Paul Warwick attempts to halt the Leinster prop
Leinster set up a Magners League final against the Ospreys by beating Munster in a bruising contest at the RDS.
Jonathan Sexton kicked Leinster ahead in a frantic first half before Ronan O'Gara levelled before the break.
O'Gara edged the defending champions into the lead after the restart but Sexton's superb exchange of passes set up Rob Kearney for the decisive try.
Sexton added six more points and despite late pressure, Munster were unable to muster a scoring response.
The match started at a ferocious pace and the frantic nature of the proceedings continued for the remainder of the first half.
Sexton, back after a month out because of a broken jaw, missed an early wind-assisted opportunity for Leinster before Keith Earls threatened the home team's defence at the other end with a surging run.
Big hits were the order of the day in the opening minutes but Shane Horgan over-stepped the mark on 12 minutes with a dangerous tackle on Niall Ronan which resulted in the Leinster wing being sin-binned.
Despite temporarily being a man down, Leinster edged ahead six minutes later as Sexton slotted a penalty.
Inevitably, Munster responded quickly as the lively Nick Williams threatened the Leinster line and Paul Warwick hit the woodwork with an attempted drop-goal after the ball had been recycled.
Munster did level on 29 minutes as O'Gara judged the wind expertly to kick a penalty.
The score remained a 3-3 at the break to leave the match perfectly poised for the second period.
Munster edged ahead 10 seconds after the resumption as O'Gara slotted a long-range drop-goal after Malcolm O'Kelly had failed to gather the fly-half's restart.
But the score only served to stir the Leinster backs to produce the crucial moment of the match three minutes later.
The score was all about Sexton's attack-minded instincts as the Leinster fly-half exchanged passes with Gordon D'Arcy in the Munster 22 before releasing Kearney to score in the corner.
Sexton added the difficult conversion and when he kicked another penalty on 50 minutes, Leinster were suddenly 13-6 ahead.
In addition to Leinster's silky play behind the scrum, Jamie Heaslip was inspiring his pack with a series of crucial interventions - including a couple of dangerous charges into opposition territory.
Leinster looked unfortunate not to be awarded a penalty try three minutes later as Tomas O'Leary's high challenge on Cian Healy stopped a certain touchdown.
Sexton kicked the three points but Nigel Owens' decision not even to yellow card O'Leary appeared highly questionable.
Munster produced a five-minute period of sustained pressure after the hour mark but Leinster held firm to register their fourth straight win over their Irish rivals.
O'Gara missed a difficult chance to cut Leinster's lead but the comeback never really looked on as Michael Cheika's side set up a decider against the Ospreys at the RDS on 29 May (1830 BST).
Leinster: Kearney, Horgan, O'Driscoll, D'Arcy, Nacewa, Sexton, Reddan; Healy, Fogarty, Wright, Hines, O'Kelly, McLaughlin, Jennings (cpt), Heaslip.
Replacements: Strauss for Fogarty 72, van der Linde for Wright 46, Hogan for Hines 79
Not Used: O'Donohoe, McFadden, Dempsey, O'Brien..
Munster: Warwick, Howlett, Earls, de Villiers, Mafi, O'Gara, O'Leary; Horan, Varley, Hayes, O'Callaghan, O'Driscoll, Quinlan, Ronan, Williams.
Replacements: D Hurley for de Villiers 60, Stringer for O'Leary 65, D Ryan for Hayes 56, Coughlan for Ronan 61, Wallace for N Williams 53
Not Used: Flannery, Deasy.
Referee: Nigel Owens (WRU)