Ian Madigan climbed off the bench to rescue Leinster and book a place in the RaboDirect PRO12 final against Glasgow Warriors following a thrilling 13-9 semi-final win over Ulster.
Madigan scored the only try of the match on 71 minutes after a heroic defensive effort from Ulster, ensuring the defending champions will be back at the RDS on May 31.
Fly-half Paddy Jackson had kicked Ulster into a 9-0 lead shortly after half-time but Jimmy Gopperth brought Leinster back to within three before Madigan struck.
The first half was frenetic with huge hits flying in all over the pitch but defences were on top with neither side giving anything away.
Indeed, after Leinster prevailed by just two points against Ulster last month this clash was always going to be a close affair and so it proved.
Ulster were handed the first chance to break the deadlock on four minutes but South African scrum-half Ruan Pienaar missed the target from long range.
But Jackson made no mistake from closer in after some impressive work from Pienaar and Tommy Bowe.
Mistakes began to creep in when both sides were on the attack but both were imperious in defence and the scores remained lock at 3-0 to Ulster until just before the interval.
By that stage Leinster were down to 14 men after Gordon D’Arcy was sent to the sin bin for a late tackle on Bowe but it was the hosts’ going offside after a strong carry from centre Darren Cave that gave Jackson the chance to double his points haul.
He duly obliged and while Leinster flew out of the blocks in the second half, Ulster held firm and indeed stretched their lead to 9-0 after D’Arcy, back into the fray, was penalised.
Jackson made it three from three shortly after Brian O’Driscoll went off to a standing ovation but Leinster finally got on the scoreboard on 58 minutes through fly-half Gopperth.
Replacement Sean O’Brien was having an impressive impact and on 63 minutes another penalty from New Zealand Gopperth brought the defending champions to within three points.
With nine minutes on the clock another replacement Madigan finally got the first try of the match, breaking the previously unflinching Ulster line to dot down.
Gopperth added the extras but Ulster set about laying siege to the Leinster try-line. James McKinney, man of the match last week against Munster and on in place of Jackson, kicked to the corner after the visitors were awarded a penalty but a huge defensive stand from the hosts kept them out.