Normally in matches like this there are no winners, just survivors. The truth is always and only in the action, and in this pulsating match Munster proved that when they really, really absolutely have to, they can pull one out of the bag.
They were the better team on the day, dominant in the first half, sharp, precise and alert. Their pack had a voracious appetite at the breakdown and they were just that little bit more controlled and composed in the red zone.
More importantly they scored precious tries, something they had been singularly unable to achieve in seven matches, but when you are like a dog without a bone, sometimes that hunger takes you to the edge. Munster had that edge and in scoring those two tries they also managed to keep Leinster tryless.
Once again the denial was more down to design than luck; they really were not giving anything away to the European champions. They say anger is an energy and a huge amount of introspection probably went into the pre-match preparation. They know how Leinster play and they know what level they need to play at to beat them. All they needed was a little bit of anger sustained by a little bit of composure.
Both teams played a breathless form of the game. You sensed maybe that Munster's three-quarter line probably weren't skilful enough to prise open a very efficient Leinster line but they managed it three times in the first half, only scoring once. Lifeimi Mafi, so often a serial under-performer in this fixture, suddenly had the game of helter skelter and broken-field opportunities which suited him and he was dangerous all day.
It looked like he had taken up a fairly innocuous position 10 yards behind a Munster breakdown in the Leinster 22. He was effectively out of the game as Munster, you thought, would just bash the peripheries. Conor Murray, out of the corner of his eye, caught Mafi making a run, normally from such a deep position Leinster could shut that direction off. He took a diagonal line and a stutter step which took him half a metre further forward than Eoin Reddan anticipated, took him out of the tackle and as he straightened, even though the ball was put behind Doug Howlett, Luke Fitzgerald had come in and all Howlett had to do was catch and score.
There were no high-fives, there were no wild celebrations -- Munster knew the winning of this game would happen somewhere after the 75th minute -- but it did galvanise them and the fact that they got over Leinster's line fortified their belief in themselves and they dominated with real conviction the next 30 minutes.
Both sides could dwell on the possibilities at half-time. Leinster can be a 20-minute side when all they needed to do was wrap it up; they did not at that stage look tired.
The second half started with that anticipated 20 minutes of dominance for Leinster. Jonny Sexton worked Brian O'Driscoll free deep in their half and O'Driscoll reciprocated with a wondrous one-handed reverse flick to set the outhalf on his way. Leinster went through 23 phases and Munster must have broken every law in the statute book to deny them a try.
Donncha O'Callaghan got binned, but Leinster still could not break them down. Another case in point in Munster's determination and their added value in the tackle. Sean O'Brien, who had run out of diesel early in the second half, chipped a ball down the right. The ball, as a rugby ball does, refused to go over the try line for Felix Jones to touch down, even though it had the forward momentum, and Jones had to place it over the touch line.
Leinster were in the mood now and their form was irresistible. Off a Nathan Hines tap, Jamie Heaslip and Richardt Strauss worked a double wrap and Strauss was stopped not inches but millimetres from the line. Reddan, after his superb performance last week, was not as sure at the base as he had been and a determined David Wallace tackle caught him by the leg and carried him three or four yards back. Coughlan baled in and the ball was turned over. The Leinster back row looked a pale shadow of itself, even though they fought a reasonable rearguard action. In between times Jones put in two excellent tackles on O'Driscoll and Fitzgerald.
After the third 20 was over Munster assumed control and Leinster did not help themselves by trying to run from deep, even though the wind had changed and was no longer a factor. This caught them out and they tried to run ball out of their 22. Ronan O'Gara, already on a penalty advantage, cross-kicked to Keith Earls, who showed great composure to collect, jump inside Isa Nacewa and roll over from a Shane Horgan tackle.
The usual bench clearances took place in the final quarter and Munster kept their shape better and closed out amid some drama. Nigel Owens' penalty try at the death was a little baffling but Munster deserved their win. Credit to both sides to compete at this level at this stage in the season.