Pro12: Leinster 19-6 Ulster
Leinster (10) 19
- Gopperth 4
Ulster (6) 6
- Jackson 2
Leinster moved up to second place in the Pro12 standings after outplaying Irish rivals Ulster at the RDS.
Number eight Jordi Murphy got the only try of Saturday night's game which was a repeat of the 2013 final won by Leinster at the same venue in May.
Ulster had led 6-3 thanks to two Paddy Jackson penalties but Jimmy Gopperth landed one from three penalty attempts and converted Murphy's 36th-minute try.
Gopperth added three penalties after the break to leave Ulster empty-handed.
It was a fourth league defeat of the season for Mark Anscombe's side who fall to fifth place in the final.
Leinster, anxious to avoid a third successive defeat, showed more intensity and will wonder why their half-time lead was not more than 10-6.
The key moment in front of a sell-out Dublin crowd, came in the 36th minute.
Seconds after Ulster openside Sean Doyle had been binned for not rolling away, Leinster winger Luke Fitzgerald broke down the left wing and set up Murphy for the try.
It was the least Matt O'Connor's men deserved as they had dominated possession in the first half.
Ulster brought on regular starters Ruan Pienaar and Jared Payne in the third quarter, but the move failed to revive the visitors' fortunes.
Two offside infringements and Tom Court's bringing down of the scrum gave Kiwi fly-half Jimmy Gopperth the opportunities to kick the nine points scored in the second half.
Ulster now must regroup for another tough Irish derby as they host Munster on 3 January.
The only blot for Leinster came when second row Sean O'Brien dislocated his shoulder in the second half and that could be bad news for Ireland as well as his province.
Leinster: Kirchner, D. Kearney, Macken, Reid, Fitzgerald, Gopperth, Boss, Bent, Dundon, Moore, Cullen, McCarthy, Ruddock, O'Brien, Murphy.
Replacements: Madigan for Reid (66), L. McGrath for Boss (79), Tracy for Dundon (66), Ross for Moore (66), Denton for Cullen (72), Ryan for O'Brien (53). Not Used: J. O'Connell, Fanning.
Ulster: R. Andrew, Trimble, Cave, L. Marshall, Gilroy, P. Jackson, P. Marshall, Black, Herring, Fitzpatrick, Stevenson, Tuohy, Diack, Doyle, Wilson.
Replacements: Payne for R. Andrew (50), Allen for L. Marshall (57), Pienaar for P. Marshall (50), Lutton for Fitzpatrick (72), McComb for Stevenson (68), McComish for Doyle (67). Not Used: Annett, Court.
Sin Bin: Doyle (36).
Ref: John Lacey (Ireland).