|Guinness Pro12 semi-final|
|Leinster (13) 30|
|Tries: Nacewa, Heaslip, Cronin Cons: Sexton 3 Pens: Sexton 3|
|Ulster (11) 18|
|Tries: Gilroy 2 Con: Jackson Pens: Jackson 2|
Leinster remain on track for a third Pro12 title in four seasons after beating Ulster at the RDS on Friday.
The hosts proved too good for Ulster who were attempting to become the first away team to win a semi-final.
Isa Nacewa's early try and Johnny Sexton's boot had the hosts 13-0 up but Ulster hit back with two Paddy Jackson penalties and a Craig Gilroy try.
Jamie Heaslip and Sean Cronin tries put Leinster 30-11 up before Gilroy snapped up his second try.
It was Ulster's sixth defeat in seven league semi-finals, while Leinster kept up their enviable 100% per cent record in Pro12 play-offs.
The victory sent Leinster through to a 28 May decider in Edinburgh where they will play either Connacht or defending champions Glasgow.
Leo Cullen's men had all the early pressure in Dublin, ominously building a 13-0 advantage inside 16 minutes with captain Nacewa touching down and 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 Gilroy's try just before half-time.
Trailing 13-11, the Ulstermen's momentum was broken by number eight Heaslip's 47th-minute try, though.
Replacement Sean Cronin's effort past the hour mark, coupled with Sexton's unerring boot, had Leinster seemingly out of reach at 30-11.
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.
Leinster: I Nacewa (c); D Kearney, G Ringrose, B Te'o, L Fitzgerald; J Sexton, E Reddan J McGrath, R Strauss, M Ross, D Toner, M Kearney, R Ruddock, J Murphy, J Heaslip.
Replacements: S Cronin, P Dooley, T Furlong, R Molony, J Conan, L McGrath, I Madigan, Z Kirchner.
Ulster: J Payne; A Trimble, L Marshall, S McCloskey, C Gilroy; P Jackson, R Pienaar; C Black, R Best (c), R Lutton, P Browne, F van der Merwe, I Henderson, C Henry, S Reidy.
Replacements: R Herring, K McCall, A Warwick, R Diack, R Wilson, P Marshall, S Olding, D Cave.