Just last month, there were hopeful whispers these two might be seeing some more of each other in the Heineken Cup final. Last night the more forceful opinion from the capacity crowd of 19,750 was that this might as well have been the Magners League final. Leinster will play the Ospreys in the actual decider here on 29 May but you don't envy the Welsh. It may have taken the home side some time to get going but when they finally ignited they were unstoppable, mixing bruising defence that ground their great rivals down with strands of magic in attack.

They played the opening half with a dictating wind at their backs but spent much of it with Munster in their faces. The visitors looked the livelier and more adventurous, running back, clearing kick after clearing kick with Paul Warwick dangerous. But the Australian was one of the few that opened gaps in a 40 minutes that was brutal not brilliant, and full of heavy hits but few light feet.

Leinster's saving grace was their intensity. On the back foot they were like greyhounds let loose on hares and, when Munster kicked in behind, Rob Keaney had the safest hands in the house. Not that such an accolade was hard to achieve in a half of knock-ons. In fact Doug Howlett should have been away more than once only to repeatedly spill ball in good positions down the right.

Jonathan Sexton had missed an early penalty only to make amends on 16 minutes with the game's opening score. But, if Leinster were expecting an explosion of points just like in the last meetings between the two here in Dublin, they were mistaken. In fact a Warwick chip nearly sent Alan Quinlan over the line while Ronan O'Gara thought he'd earned himself an assist as Lifeimi Mafi went close too. The pressure paid off though and, by the 28th minute, O'Gara smashed a penalty into the gale and between the posts.

As for the latest instalment of that sideshow between the two Irish out-halves, both had it hard on and off the ball. Shane Horgan was sent to the bin after 13 minutes for a reckless and needless tackle on a mid-air O'Gara. His opposite number was in the wars too, Sexton getting more than a few studs to the stomach when finding himself on the wrong side of a ruck. But at three apiece at the interval, it would have been O'Gara the more confident with that wind awaiting him at the restart.

He didn't waste time making the most of the elements when returning to the field. The second half was only 18 seconds young when Niall Ronan fired the ball in his direction and he landed a big drop-goal. But then came the moment when Leinster finally realised their potential in the backs. With 44 minutes gone, Brian O'Driscoll looped a pass to Sexton who sprinted clear before firing wide to Kearney who went over in the corner. The conversion was sweet too.

What Leinster did next was like the Munster of old. They followed up the try with some big scrums that sapped the energy from their opponents and man-of-the-match Jamie Heaslip helped lay down a marker. And they picked their fights too, one such scuffle allowing Sexton to add three more points to make it 13-6. It was more soon after. Tomás O'Leary miraculously stopped John Fogarty on the line with a shuddering hit. However, it was wrongly adjudged to be high and Sexton was allowed nail his third penalty.

There were still 24 minutes left at that point but with O'Gara failing with two penalties and some fine defensive work down the stretch, it was game over. And on this form, the Magners League should be over too.

LEINSTER R Kearney; S Horgan, B O'Driscoll, G D'Arcy, I Nacewa; J Sexton, E Reddan; C Healy, J Fogarty, S Wright; N Hines, M O'Kelly; K McLaughlin, S Jennings, J Heaslip Subs CJ van der Linde for Wright, 45 mins; R Strauss for Fogarty, 72 mins; Wright for Healy, 73 mins; T Hogan for Hines, 78 mins Sin bin Horgan 13-23 mins Scorers Sexton, 3 pens, con; Kearney, try

MUNSTER P Warwick; D Howlett, K Earls, J de Villiers, L Mafi; R O'Gara, T O'Leary; M Horan, D Varley, J Hayes; D O'Callaghan, M O'Driscoll; A Quinlan, N Ronan, N Williams Subs D Wallace for Williams, 53 mins; D Hurley for De Villiers, 59 mins; J Coughlan for Ronan, 61 mins; P Stringer for O'Leary, 64 mins; D Ryan for Hayes, 65 mins Scorers O'Gara, pen, d-g

Referee N Owens (Wales)