Leinster secured an impressive 20-19 away win over rivals Munster in a tight game at Thomond Park.
Gavin Coombe's converted try put Munster ahead 7-6 in the first half.
Tries in the second half from Scott Penny and Dan Sheehan edged the United Rugby Championship leaders ahead.
Munster were awarded a penalty try and a score from replacement Patrick Campbell set up a tense finale, but it was not enough to rescue the game for the hosts.
The win cements Leinster's position at the top of the URC table after an unbeaten start to the season, with Leo Cullen's men eight points clear of the Stormers after 10 matches.
The interprovincial derby was back in its traditional festive slot for the first time in three Covid-interrupted years, with a full house and electric atmosphere at Thomond Park.
After a frantic start, fly-half Ross Byrne settled the game down with a successful penalty to put the visitors ahead.
An arm-wrestle of a first quarter followed, with back-and-forth action as both sides struggled to gain the ascendancy.
Byrne added to his side's tally with another penalty just before the end of the first quarter.
A spell of territory for Munster in the Leinster 22 was rewarded with a try from number eight Coombes, who powered over from a short distance. Carberry added the extras to put his side ahead by a point.
The final action of the first half was an unsuccessful penalty attempt from Byrne. The game went into the break on a knife-edge, with the hosts 7-6 ahead.
Munster gained the ascendancy at the start of the second half and several acts of Leinster indiscipline culminated in a penalty try for Munster and a yellow card for number eight Max Deegan, who was judged to have illegally prevented Niall Scannell from grounding the ball.
Leinster hit back shortly after, with Penny crashing over following patient build-up from Leinster who started to dominate in terms of territory and possession.
The visitors went ahead with a try from hooker Sheehan, who tapped a penalty and used his powerful leg-drive to burrow over the line. Byrne added the extras with an impressive conversion from the corner.
Munster continued to battle and hit back with a try from replacement full-back Campbell, assisted by an excellent 20-yard pass from Craig Casey to put him into space in the corner.
Munster: Daly; Nash, Frisch, Crowley, Earls; Carbery, Murray; Kilcoyne, N Scaannell, Ryan, Kleyn, Beirne, O'Donoghue, O'Mahony (capt), Coombes.
Replacements: Barron, Wycherley, Salanoa, McDonald, Kendellen, Casey, R Scannell, Campbell.
Leinster: Keenan; Larmour, Ringrose (capt), Osborne, Lowe; R Byrne, N McCarthy; Porter, Sheehan, Healy; Baird, J McCarthy; Ruddock, Penny, Deegan.
Replacements: McKee, Milne, Abdaladze, Molony, Conan, McGrath, H Byrne, Turner.