Leinster's Luke Fitzgerald tackles Jerry Flannery of Munster
Leinster (0) 0
Munster (3) 18
Tries: Melck, Howlett
Two late tries sealed victory for Heineken Cup holders Munster over Magners League champions Leinster at the RDS in Dublin on Sunday night.
South African Justin Melck touched down in the 69th minute to swing the derby in the Munster men's favour.
All Black legend Doug Howlett put a gloss on the scoreline with a try in the last minute.
Ronan O'Gara kicked the rest of the points as Munster move second, just one point behind the Ospreys.
The match was on a knife edge until Melck's try.
The former Western Province and Stormers back-rower, on a three-month contract, squeezed through a gap between Jamie Heaslip and Rob Kearney to put the visitors 11-0 ahead.
At the death, Howlett raced on to a deft kick through from O'Gara to score under the posts.
It was Leinster's first league defeat at home to Irish opposition in five years and the manner of the loss will worry coach Michael Cheika and his management team.
Having lost twice to Leinster last season and not beaten them since that famous European success at Lansdowne Road in 2006, revenge will be sweet for Munster.
Leinster: G Dempsey; S Horgan, B O'Driscoll, F Contepomi, L Fitzgerald; J Sexton, C Whitaker; R McCormack, B Jackman, CJ van der Linde; L Cullen (capt), M O'Kelly; R Elsom, S Jennings, J Heaslip.
Replacements: Kearney for Horgan (53), Wright for McCormack (41), Hogan for O'Kelly (70).
Munster: K Earls; D Howlett, R Tipoki, L Mafi, I Dowling; R O'Gara, T O'Leary; M Horan, J Flannery, J Hayes; P O'Connell (capt), D O'Callaghan; D Ryan, D Wallace, J Melck.
Replacements: Stringer for O'Leary (73), Pucciariello for Horan (72), Sheahan for Flannery (51), Quinlan for D. Ryan (55), O'Sullivan for Melck (77).
Referee: Simon McDowell (IRFU)