You'd think that Leinster might have had somewhere in the back of their minds the idea that this would be the night their remarkable run of success over Munster would come to an end.
After all, Tony McGahan had backed his men into a corner by declaring last week that it was win or bust. "There is no way in the world we can afford to lose this game," he had said. They didn't. But we never thought they could extend their barren run of tryless performances against Leinster and still win.
Naturally enough, Ronan O'Gara was the man who could complete that equation. Handed a kick on the 15-metre line in the last minute of the game, O'Gara didn't just nail it, he put it over the black spot. It reminded you of a kick he made against Saracens from a similar position back in early 2000 when Munster were on their way to their first ever Heineken Cup final. Not much has changed in that department.
The relief all around Thomond Park was massive. When the crowd calmed down, though, thoughts turned to Paul O'Connell, who had by then gone to hospital for an X-ray on an ankle. He had landed on it from a height, at a lineout early in the second half, and, given the amount of pain he was in, it would be remarkable if there was no damage done. They will need him in Brive.
And they will need to score tries there too. They got very few of the 50-50 calls in the first half here, and the majority of them after the break. That second-half turnaround gave them momentum, and O'Gara did the rest, with seven successes from eight attempts.
And how they needed it. Leinster were 20-9 ahead at half-time and had never looked so comfortable in this fixture. The break couldn't come quickly enough for the home team, whose primary attacking weapon had been David Wallace on the carry. Then, Leinster would slow them at the breakdown and everything after that looked to be going nowhere.
For Joe Schmidt's mob, however, they had lots of ways to go forward. The slickest had been the set-piece move off an excellent scrum -- Leo Cullen had opted for a reset after Munster were done for early engagement -- mid-way through the first half. A lovely combination between the excellent Isaac Boss and Brian O'Driscoll, and then O'Driscoll and Isa Nacewa, saw the full-back grubber for Shane Horgan to mark his 200th game for Leinster with a try.
Sexton couldn't make the conversion from out wide, but he had nailed three penalties to two from O'Gara at that point and suddenly Leinster had a 14-6 lead.
After that they looked to be cruising. Boss was buzzing, so was Jamie Heaslip, and Gordon D'Arcy was getting more metres than in a long time. All you could see was six from six for Leinster and perhaps 10-0 on tries? Munster lost Johne Murphy to the bin on 36 minutes -- Sexton punished it and Munster were staring into the abyss.
The game swung in the third quarter though. Leinster started to run into areas -- especially in the wide channels -- where they could be driven into touch, and where they had traded well at the breakdown in the first half, they were being blown out of it in the second.
O'Gara had four unanswered shots to swing Munster into a 21-20 lead by 62 minutes, and the last came with Brian O'Driscoll being binned for not getting off Keith Earls after he had countered. The fans roared approval as the Ireland captain -- clearly miffed -- made his way off. That was the light at the end of their tunnel.
Sexton pulled the lead back for Leinster, however, just four minutes later on one of their rare sorties into the red zone, but they couldn't put out the fire that was burning in the home team. Denis Leamy did very well when he came on, and Sam Tuitupou gave added steel to their midfield. Still they couldn't score tries, but such was the flow that all they needed was another opening for three points and they knew O'Gara would close it.
With the Ospreys drawing against Cardiff, Munster are still not guaranteed a home semi-final in this competition, but they are motoring on. Brive will be a different sort of challenge, and if O'Connell doesn't make it then it will be a bigger battle again. As for Leinster, the idea that this was the night to give up their advantage over Munster drifted miles away when they were running through the moves and winning the game with their eyes closed. They will be every bit as angry at letting this slip, as Munster will be happy at having stopped the one-way traffic.
Scorers -- Munster: R O'Gara 7 pens, P Warwick 1 pen. Leinster: S Horgan try; J Sexton 6 pens.
Munster: F Jones (P Warwick 76); D Howlett, J Murphy (yc 36-46, S Tuitupou 63), L Mafi, K Earls; R O'Gara (P Warwick 42-45 blood), C Murray (P Stringer 67); W du Preez (M Horan 67), D Varley, T Buckley (J Hayes 67), D O'Callaghan, P O'Connell (capt)(M O'Driscoll 47), D Ryan (D Leamy 54), J Coughlan, D Wallace.
Leinster: I Nacewa; S Horgan (F McFadden 67), B O'Driscoll (yc 61-71), G D'Arcy, L Fitzgerald; J Sexton, I Boss (E Reddan 58); C Healy (H van der Merwe 57), R Strauss, M Ross; L Cullen (capt), N Hines; K McLaughlin (M Ruddock 64), J Heaslip, S O'Brien.
Referee: A Small (England)