Leinster moved level on points with Ulster at the top of the Pro12 following a 25-14 win over Munster at the Aviva Stadium on Saturday.
Wing Isa Nacewa scored twice for Leinster, while Ireland fly-half Johnny Sexton added two conversions and slotted over a pair of penalties to secure victory over their Irish rivals in Dublin.
The two sides boasted identical records going into the contest having won four of their opening five games, but Leinster started the brighter as Sexton's pair of three pointers put them 6-0 ahead, only for Peter O'Mahony - making his first Munster start since May 2015 - to power over following a rolling maul and turn matters in their favour.
But Sexton set up Nacewa to make it 11-7 five minutes before the interval and 10 minutes after the break the New Zealander had his second, taking advantage of the overlap to cross in the left-hand corner from Rob Kearney's long pass.
Jamison Gibson-Park then put the result beyond doubt by touching down after Ronan O'Mahony and Tyler Bleyendaal both failed to deal with a chipped kick over the top, with Jaco Taute's late score a mere consolation.
Leinster's failure to score a fourth try that would have sealed a bonus point means Ulster remain top on points difference.
Munster dropped out of the top four as Glasgow Warriors leapfrogged them in the table by surviving a scare against winless Zebre.
Fraser Brown and Leonardo Sarto scored tries and and Sean Lamont crossed for a double as the Warriors held on for a 33-28 win despite seeing Matt Fagerson and Rob Harley sin-binned.
Carlo Canna kicked a late penalty to seal a bonus point for the Italians, who saw Johan Meyer and Giulio Bisegni receive yellow cards.
Elsewhere Scarlets came from behind to beat Newport Gwent Dragons 31-27 and record a third straight win.