Munster claimed the Magners League title at Thomond Park on Saturday, denying Irish rivals Leinster a trophy double thanks to a 19-9 scoreline.
Tries by wings Doug Howlett and Keith Earls, plus a penalty try, took them to a deserved win which was just reward for dominating the regular term.
Fly-half Jonathan Sexton scored all Leinster's points, but fatigue from last week's Heineken Cup battle with Northampton seemed to affect them in the latter stages, which the home side controlled.
Traditionally, Munster have had the edge over their rivals, but it is the Irish underachievers who have taken over the mantle as the country's dominant side in recent times.
Although the hosts snapped a five game losing run against the Dublin outfit in April, with a 24-23 home victory, the newly crowned European champions were still favourites for this encounter.
However, Munster ran away with the league title and comfortably disposed of the Ospreys in the semi-final. And in the 13th minute, former All Black Howlett went over for the first score, fly-half O'Gara converting from out wide.
As the half wore on, Leinster managed to gain more of a foothold and regularly threatened, but numerous mistakes curtailed their progress. In fact, in a frenetic and end-to-end opening period, both sides looked to keep ball in hand, but it was the away side who were eventually rewarded for their endeavours with a penalty from Sexton.
7-3 to the hosts at half-time was then reduced to one point from powerful Leinster play.
Donncha O'Callaghan then succumbed to the visitors' pressure and was subsequently sin-binned. Sexton converted the resultant penalty and then added another on the hour mark to help Leinster into the lead for the first time in the match.
With just under a quarter-of-an-hour to go, Munster regained the advantage through a piece of magic from O'Gara. The Limerick outfit already had a penalty advantage but with most people expecting him to go for the drop-goal, he produced a deftly weighted cross-field kick for Earls to score. O'Gara missed the extras but a late penalty try sealed the win.
Tries: Howlett, Earls, Penalty
Con: O'Gara 2
Pen: Sexton 3
Munster: 15 Felix Jones, 14 Doug Howlett, 13 Danny Barnes, 12 Lifeimi Mafi, 11 Keith Earls, 10 Ronan O'Gara, 9 Conor Murray, 8 James Coughlan, 7 David Wallace, 6 Donncha Ryan, 5 Paul O'Connell (capt), 4 Donncha O'Callaghan, 3 John Hayes, 2 Damien Varley, 1 Marcus Horan.
Replacements: 16 Mike Sherry, 17 Wian du Preez, 18 Stephen Archer, 19 Denis Leamy, 20 Niall Ronan, 21 Peter Stringer, 22 Paul Warwick, 23 Johne Murphy.
Leinster: 15 Isa Nacewa, 14 Shane Horgan, 13 Brian O'Driscoll, 12 Fergus McFadden, 11 Luke Fitzgerald, 10 Jonathan Sexton, 9 Eoin Reddan, 8 Jamie Heaslip, 7 Shane Jennings, 6 Sean O'Brien, 5 Nathan Hines, 4 Leo Cullen (capt), 3 Mike Ross, 2 Richardt Strauss, 1 Heinke van der Merwe.
Replacements: 16 Aaron Dundon, 17 Cian Healy, 18 Stan Wright, 19 Devin Toner, 20 Kevin McLaughlin, 21 Paul O'Donohoe, 22 Ian Madigan, 23 Eoin O'Malley.
Referee: Nigel Owens (Wales)
Assistant referees: Tim Hayes (Wales), David Jones (Wales)
Television match official: Nigel Whitehouse (Wales)
Timekeeper: Andrew Baird