When these sides met nearly two months ago, Munster put such a premium on winning that there was nowhere for them to go if they didn't deliver. They did, of course. It wasn't that much different in front 25,822 spectators in Thomond Park last night.
There was no guard of honour for the European champions onto the field, and neither was there much room for them to catch their breath thereafter. In what was a terrific game of rugby -- the pace of which had as much to do with the away team as the home one -- Munster played the game they are best at: coming round the corner in waves, never letting their focus slip, maintaining the sort of intensity that has set them apart until this season when they began to look ordinary on the big days. This was a throwback.
To make it work they need not just willing carriers but effective ones, and it's been a problem for them all season -- getting good go-forward from their grunts. Compared to Leinster for example, the Reds are short of the explosive quartet that is Cian Healy, Richardt Strauss, Sean O'Brien and Jamie Heaslip. David Wallace is their one man who can manufacture something from a standing start. He was awesome last night, picking up the man-of-the-match award with a massive contribution.
Credit to his colleagues Damien Varley and Donnacha Ryan and James Coughlan, who carried manfully and defended with great concentration. Paul O'Connell meanwhile, in his last game of the season, looked like he was just hitting the right pitch. He too had a huge game.
The aggregate was that Leinster got no time off at all. Perhaps their exertions of Cardiff last weekend undermined their effort but with the stiff breeze at their backs in the first half they went for broke. Penalties were run without pause; ball won in the shadow of their own posts was as likely to be kept in hand as punted -- more likely in fact.
And at half-time, when Munster were only 7-3 in front despite having had most of the ball, you wondered if Leinster's policy would pay off, that if they could summon the same energy after the break it would mean huge pressure on Munster's defence. And in this fixture that would mean tries for Joe Schmidt's mob.
Not this time. Unlike their last meeting, when Munster gradually overhauled their opponents in the second half with a string of penalties, this time they added two tries to Doug Howlett's first half effort -- carved out by the excellent Lifeimi Mafi -- which had them in the lead after 12 minutes, and played altogether more forceful rugby.
Their plan throughout was to open a big enough blind side for Mafi to attack on a cutback, and it always had Leinster in trouble. Mind you, some of that involved doing so off their lineout, which they shortened regularly in the first half, but still managed to lose three throws in the first half an hour. And still they coped.
Their scrum too has been a source of angst for Tony McGahan this season but it finished in cruise control, albeit with Mike Ross and Heinke van der Merwe off the field, delivering a penalty try with a minute left, to make them safe.
How the crowd enjoyed that. Over the years their supporters have been an integral part of the overall effort and they made a big contribution here. Same venue as a fortnight ago against the Ospreys, but a different world. And in that world and in this sort of mood Munster still can be very difficult to live with.
The result and the way they brought it about will give McGahan heart for next season. He has had a hard time of it -- more so than he deserved -- and this will feel good. Even so, if he doesn't buy in an industrial ball carrier to complement Wallace -- or to replace him when he's away -- hard times will return.
They needed a big opening quarter to this game and got it. More importantly they needed points. And lo and behold, after six barren games against Leinster they had a try, courtesy of that Mafi/Howlett combination. They should have lost Marcus Horan to the bin for an off-the-ball tackle on Brian O'Driscoll a while later, but escaped, and at the break were four points up after Jonny Sexton had kicked a penalty.
The Sexton v O'Gara battle was one of the attractions of the night: they had different sorts of games -- the Leinster outhalf putting himself about a fair bit, the Munster 10 getting off the floor after a concussive-looking encounter with Isa Nacewa to direct their endgame.
It was O'Gara who had done what Leinster failed to do when they had an advantage play close to their opponents' line. You have to go for the big play -- Leinster hadn't done it early in the second half and after massive pressure only came away with three points after Donncha O'Callaghan was binned; Munster through O'Gara, in the same situation on 66 minutes, punted wide to Keith Earls, who slipped two tackles to score.
That came a few minutes after Sexton had kicked his third shot to put Leinster 9-7 ahead. Suddenly their lead was gone, and Munster stayed in control for the last quarter until at the death they had to defend their line against a try that wouldn't have mattered had it been scored. It wasn't. By then they had done enough to win their third Celtic title. No arguments from any quarter.