Rob Kearney scored the only try of the night for Leinster
Munster lost their grip on the Magners League title as they were beaten 16-6 by reigning Heineken Cup champions Leinster in the second Play-Off semi-final in Dublin.
It means that the inaugural Magners League Grand Final will now be between Leinster and the Ospreys at the RDS on Saturday, 29 May (kick-off 6.30pm).
Leinster won the right to host the Grand Final because they finished on top of the regular Magners League table. It means they can expect another sell-out crowd of 19.750 when the top placed Welsh region arrive in the Irish capital in two weeks time.
It will be a special occasion for Leinster coach Michael Cheika as he takes charge of the side for the last time before heading to France to take over the coaching reigns at Stade Francais Paris.
It will also be an emotional night for two Leinster stalwarts, lock Malcolm O'Kelly and full back Girvan Dempsey, who are hanging up their boots after distinguished service to club and country. It will also be a final outing for the Ospreys' former New Zealand No8 Filo Tiatia before he retires.
Leinster beat the Ospreys 18-11 at the Liberty Stadium at the start of the season and they completed the double with a 20-16 triumph at the RDS on 16 April. Whichever team wins the battle between the Heineken Cup semi-finalists and quarter-finalists will become the first team to win the Magners League title three times.
Finals Edition: Listen to the best guide to the European Rugby Cup Finals weekend in Dublin, which sees Leinster Rugby take on Stade Francais Paris at the RDS on Friday night in the Amlin Challenge Cup Final and then ASM Clermont Auvergne tackle Toulon in an all-French affair at the Aviva Stadium on Saturday.