Leinster 30 Ulster 18
Leinster kept up their enviable 100% record in Guinness PRO12 play-offs with a clinical 30-18 win over Ulster at the RDS.
The Irish province's seventh straight league semi-final success sent them through to next Saturday's decider in Edinburgh where they will play either Connacht or defending champions Glasgow Warriors.
Leo Cullen's men had all the early pressure in Dublin, ominously building a 13-0 advantage with captain Isa Nacewa touching down and Jonathan Sexton kicking the other points.
But resilient Ulster turned things around in the second quarter, Paddy Jackson firing over two penalties and supplying the final pass for Craig Gilroy's try just before half-time.
Trailing 13-11, the Ulstermen's momentum was broken up by Jamie Heaslip's 47th-minute try, though, and replacement Sean Cronin's effort past the hour mark, coupled with Sexton's unerring boot, had the table toppers out of reach.
Gilroy completed his brace with 11 minutes left, taking his tally for the campaign to 10 tries, but Leinster had done enough to avenge last month's alarming 30-6 defeat in Belfast.
A classy finish from Nacewa rewarded Leinster for an explosive opening four minutes. Eoin Reddan's slick pass out to the right wing saw the Leinster skipper cut in past Gilroy and stretch over the line despite some last-ditch tackling.
The conversion was swung over by Sexton whose pinpoint penalty from the 10-metre line had Leinster into double figures by the 10th minute. As Leinster continued to probe off quick ruck ball and directed by their dominant half-backs, Sexton punished an Ulster offside for 13-0.
Les Kiss' side finally found some rhythm entering the second quarter, their excellent flanker Iain Henderson being thwarted just five metres out and Luke Marshall and Gilroy both breaking tackles.
Reddan came to Leinster's rescue after a dangerous Gilroy kick bobbled over their try-line, but a Jordi Murphy ruck infringement allowed Jackson to get Ulster on the board in the 26th minute..
An inspirational leg-pumping carry from Henderson had Ulster knocking on the door again, with Jackson cutting the gap further from right in front of the posts.
A Nacewa break came to nothing and then, just a minute before the interval, Gilroy squeezed over in the left corner off Jackson's flat pass, with confirmation from TMO Jon Mason. The Ulster fly-half missed the difficult conversion.
Into the second half, Ulster got no change from the Leinster defence despite a fine rip in the tackle and charging run from Henderson.
Leinster finally ended their scoreless spell - 32 minutes in all - with a smashing second try, Garry Ringrose coming back against the grain to set up an overlap and Ben Te'o's brilliant offload teed up Heaslip to crash over in the left corner.
Sexton's conversion put nine points between the sides and with the Leinster bench beginning to make an impact, he lobbed a scrum penalty through the uprights for 23-11.
Further set piece pressure provided the platform for Heaslip to send Cronin over to the right of the posts, with Sexton converting. Ulster returned the favour off scrum ball in the hosts' 22, Gilroy finishing his second seven-pointer in typically smart fashion.
Leinster's reinforced defence denied Ulster a third try late on, with lively replacement Stuart Olding going closest, as they condemned their provincial rivals to a sixth loss in seven league semi-final appearances.