Leinster moved into second place in the PRO12 standings on Saturday evening after this deserved win in a real dogfight battle over their arch Provincial rivals
Ulster took a first minute lead through the boot of outhalf Paddy Jackson, slotting over a long range penalty.
However, it was Leinster who went on to dominate the half both in territory and possession.
Leinster outhalf Jimmy Gopperth had levelled matters three minutes in with a penalty, but he was to miss two further efforts on six and 15 minutes as the home side stuttered in the red zone.
Ulster’s defence frustrated the home Province time and time again and having weathered several storms close to their line, the visitors went ahead 6-3 on 33 minutes with another Jackson penalty.
Referee John Lacey had already warned Ulster about their ill discipline at the breakdown on occasions and when openside loose Sean Doyle found himself again on the wrong side of a ruck he also found himself sinbinned on 35 minutes.
Leinster struck immediately after an overthrown lineout from the resultant penalty to touch, but British Lions winger, Luke Fitzgerald gathered and gave the perfect offload which sent No 8 Jordi Murphy in at the corner for a try. Gopperth gave Leinster a 10-6 interval lead with a superb touchline conversion.
Ulster introduced Ruan Piennar and Jared Payne early in the opening minutes of the second half and both made their presence felt.
However, it was Leinster who went into a 13-point lead by the hour mark with three penalties from Gopperth.
Ulster were more adventurous in the final quarter and came closest to scoring, but it was Leinster’s turn to be the frustrating force denying the visitors a losing bonus point as consolation at the death.