Jack Crowley's 77th-minute drop goal saw Munster edge out Leinster 16-15 in an epic BKT United Rugby Championship semi-final at the Aviva Stadium.
Leinster's double dreams were ended by a Herculean effort from Munster in their fifth successive away game, which ended with their first win in six semi-finals in all competitions.
Munster will now face the DHL Stormers in the final in South Africa after the reigning champions defeated Connacht in the first semi-final earlier on Saturday.
In a hard-fought clash in Dublin, Leinster's South African lock Jason Jenkins scored against his former employers just before half-time to give the table toppers a 10-6 lead at the break.
However, the hosts, who had rested most of their front liners ahead of next week's Heineken Champions Cup final against La Rochelle, trailed soon after the interval as a converted 45th-minute score from Tadhg Beirne put Munster back ahead.
The lead continued to change hands as Leinster replacement Joe McCarthy touched down but Ciaran Frawley's missed conversion left the advantage at just 15-13, and Munster's persistence was rewarded with Crowley's coolly-struck winner.
It was a second successive shock URC semi-final exit for Leinster, who lost the Vodacom Bulls last year, and means the Stormers will host the league decider again, with Graham Rowntree's men travelling to Cape Town in two weeks' time.
Will Connors' injury-enforced departure meant an early change for Leinster, with 2022 World Rugby player of the year Josh van der Flier sent into the fray, and the hosts took the lead when fly-half Harry Byrne turned the penalty earned into three points.
A booming 10th-minute strike from Ben Healy brought Munster level, although a Van der Flier rip in a tackle spoiled their first try-scoring opportunity.
Leinster forward Ryan Baird then had a superb solo try ruled out by Tommy O'Brien's knock-on in an aerial duel, which was spotted by TMO Ben Whitehouse.
Apart from that, Munster's defence was rock solid and rewarded with a second Healy penalty.
Frustratingly for the visitors, their well-oiled maul was foiled by turnovers, one from Max Deegan and another from Ronan Kelleher off a dummy drive.
Leinster made them pay when Robbie Henshaw's well-timed offload sent Jenkins powering over from the edge of the Munster 22, with Byrne converting.
The dam finally broke for Munster early in the second half when a well-supported Beirne drove over beside the posts. Referee Frank Murphy spotted the grounding, with Crowley converting.
A vital Beirne steal prevented a quick response from Leinster, yet having turned down a simple three-pointer, Munster watched replacement Roman Salanoa knock on near the home try-line.
Leinster took full advantage of some subsequent possession and territory, McCarthy burrowing over despite the best efforts of Keith Earls and Josh Wycherley.
Replacement Frawley's missed conversion left just two points in it, and with a high tackle and penalty counts coming back to haunt them, Leinster faltered late on.
Tireless Munster kept coming, breaking from deep following a Fineen Wycherley turnover and running back kicks, before Crowley's right boot delivered the decisive points, putting them within reach of a first trophy since 2011.
Scorers:
Leinster: Tries: Jason Jenkins, Nick McCarthy. Conversion: Harry Byrne. Penalty: Harry Byrne.
Munster: Try: Tadhg Beirne. Conversion: Jack Crowley. Penalties: Ben Healy (2). Drop goal: Jack Crowley.
Teams:
Leinster: 15 Jimmy O’Brien, 14 Tommy O’Brien, 13 Robbie Henshaw, 12 Charlie Ngatai, 11 Dave Kearney, 10 Harry Byrne, 9 Luke McGrath (c), 8 Jack Conan, 7 Will Connors, 6 Max Deegan, 5 Jason Jenkins, 4 Ryan Baird, 3 Michael Ala’alatoa, 2 Rónan Kelleher, 1 Michael Milne. Replacements: 16 John McKee, 17 Cian Healy, 18 Thomas Clarkson, 19 Joe McCarthy, 20 Josh van der Flier, 21 Nick McCarthy, 22 Ciarán Frawley, 23 Liam Turner.
Munster: 15 Mike Haley, 14 Keith Earls, 13 Antoine Frisch, 12 Jack Crowley, 11 Shane Daly, 10 Ben Healy, 9 Craig Casey, 8 Gavin Coombes, 7 John Hodnett, 6 Peter O’Mahony (c), 5 Tadhg Beirne, 4 Jean Kleyn, 3 Stephen Archer, 2 Diarmuid Barron, 1 Jeremy Loughman. Replacements: 16 Niall Scannell, 17 Josh Wycherley, 18 Roman Salanoa, 19 Fineen Wycherley, 20 Jack O’Donoghue, 21 Neil Cronin, 22 Rory Scannell, 23 Alex Kendellen.