Castres 17 Munster 25 The whole added up to more than the sum of its parts. This was a massive, cumulative effort, which went beyond even the 15 who started and the excellence of Donnacha O'Callaghan and Marcus Horan off the bench. Inevitably, it incorporated the collective will of Munster and their 9,000-strong Red Army, as ultimately Castres and the Stade de la Mediterranée were simply engulfed by an irresistible force.
Dusting off the cobwebs of just one game in the previous three months, Munster grew stronger and stronger. There were no weak links in the chain. The scrum stood up rock solid, shoulder to shoulder with a supposedly fierce Castres set-piece, as did the lineouts, apart from two overthrows to Alan Quinlan at the tail and Paul O'Connell letting one slip through his fingers late on - an isolated blemish in another tour de force from this awesome talent.
The swarming Munster defence suffocated the life out of the Castres running game. The sight of Ismael Lassissi, particularly, with ball in hand had the red shirts queuing up for a couple of early turnovers. Castres' use of the ball was unexceptional and even un-French to a degree.
A defining moment was the back three's utterly unconvincing counter-attack at 9-15 just past the hour, when Ugo Mola shuffled across field in not so splendid isolation on a switch with Romain Teulet and was hounded into touch by a swarm of red players underneath banks of the Red Army. The grip had become vice-like. Munster had them.
Then, inevitably, there were the "Cool Hand Lukes", Peter Stringer and Ronan O'Gara, pulling the strings. When O'Gara goes well, Munster go well, and like his team he grew and grew in stature, his assured place-kicking steering them home.
Long before the end it had become clear that basically it was going to come down to who applied the greater pressure, field position and then penalties. They swapped tries in injury time, with the Castres try more of a gloss than Munster's. In essence, they were largely incidental to the main plot of the match.
The wind, which also had the effect of directing most of the play along the touchline in front of the main stand, was stronger than appeared even from the shaded press box. With Castres having first use of it, Munster's first-half performance was largely one of containment.
They didn't try to make too much happen, and even when they trailed 9-0 to three penalties from the robotic Romain Teulet, the Munster players were not unduly concerned. The vocal Quinlan called them into a huddle, and presumably Mick Galwey did the talking. They threw to him and mauled, how they mauled, running the clock down and eating up the yards.
They worked their way upfield - thanks initially to a timely and crucial intercept and gallop by Quinlan - for O'Gara to land a couple of penalties before the break, and they went into the dressing-room with confidence soaring.
As they headed for the tunnel, you could see there was still enough "needle" to fill a haystack. A pumped-up Mauricio Reggiardo "bumped" into John Hayes from behind. Wrong move, Mauricio. An angry Hayes was a colossus in the second period.
Referee Chris White, in another move to diffuse tempers, made the teams come out separately and Munster emerged with cold-eyed intent.
As big as Quinlan's pre-interval play was Gregor Townsend's eye-off-the-ball knock-on off the recycled restart to the second half. David Wallace played in his face all day, helped by Townsend playing so flat, and, perhaps coupled with the additional baggage of having to constantly communicate with White on behalf of his team-mates, the Scottish outhalf - like his team-mates - cracked under the pressure.
It was also Townsend's rather blatant bridging to protect ball in the tackle which then allowed O'Gara to level matters on the next play. That was a gift-wrapped three points. Munster went for the throat and tightened their grip. After serial offender Arnaud Costes came in from the side for O'Gara to push Munster in front, the Fields of Athenry bellowed around the red half of the ground during the next injury stoppage. Just a few flags fluttered in the blue half, where they were now as quite as church mice. It seemed like a seminal moment.
Right on cue, O'Gara then began attacking the gain line, he and Stringer probing the blind side and releasing Jason Holland up the touchline (brilliantly supported by O'Callaghan) in one of those trademark high tempo bouts of recycling that admittedly weren't too commonplace. Had John Kelly not been just beaten to Rob Henderson's well weighted chip through at the end of it all, it would have been their try of the season and would have killed the game off there and then.
Cometh the hour, O'Gara - having already kicked one penalty after his guest spot on ER - remarkably landed another penalty from 50 yards.
Briefly Castres had a sniff after Teulet's fourth but, in any event, O'Gara sent over a penalty from his own half after Townsend had stiff-armed O'Callaghan at a dangerous height, and only avoided a yellow card on account of who he was (and White possibly wanted to keep aboard the one Castres player he could communicate with).
There was still work to be done and nerves to be frayed. A huge relieving roar greeted a mighty lineout steal close to the Munster line by the mighty O'Connell. Horan won another vital turnover on the deck and rumbled for O'Gara to find a huge, left-footed touch.
Then came the insurance score. The called move had been for Jason Holland to pass inside to Anthony Horgan, but these Munster players have always been encouraged to think on their feet by Declan Kidney and, realising how flat Castres were, the footballer in Holland sensed the right thing to do was chip through.
He overcooked it slightly but Olivier Sarramea (the last minute try-scoring hero in the teams' final pool match) messed up and Horgan hacked on for Kelly to calmly gather and narrow O'Gara's conversion. Kidney, Niall O'Donovan and Jerry Holland embraced with a tear or two in their eyes. That was it. They knew it. We all knew it. Even Shaun Longstaff's try couldn't dampen the party.
Scoring sequence: 21 mins: Teulet pen, 3-0; 33 mins: Teulet pen, 6-0; 36 mins: Teulet pen, 9-0; 39 mins: O'Gara pen, 9-3; 40 mins: O'Gara pen, 9-6; (half-time 9-6); 42 mins: O'Gara pen, 9-9; 54 mins: O'Gara pen, 9-12; 61 mins: O'Gara pen 9-15; 69 mins: Teulet pen 12-15; 73 mins: O'Gara pen, 12-18; 83 mins: Kelly try, O'Gara con, 12-25; 86 mins: Longstaff try 17-25.
CASTRES OLYMPIQUE: R Teulet; U Mola, E Artiguste, N Berryman, S Longstaff; G Townsend (capt), A Albouy; M Reggiardo, R Ibanez, B Moyle, I Fernandez Lobbe, N Spanghero, R Froment, A Costes, I Lassissi. Replacements: R Vignaux for Ibanez (half-time), G Delmotte for Artiguste (52 mins), S Chinarro for Costes (66-68 mins) and for Spanghero (70 mins), D Dima for Reggiardo (70 mins), O Sarramea for Teulet (77 mins). Sin-binned: Moyle (20-30 mins).
MUNSTER: D Crotty; J Kelly, R Henderson, J Holland, A Horgan; R O'Gara, P Stringer; P Clohessy, F Sheahan, J Hayes, M Galwey (capt), P O'Connell, A Quinlan, A Foley, D Wallace. Replacements: D O'Callaghan for Foley (16 mins), M Horan for O'Callaghan (23-30 mins) and for Clohessy (70 mins), M Mullins for O'Gara (46-52 mins) and for Henderson (85 mins), J Staunton for Crotty (85 mins). Sinbinned: Clohessy (20-30 mins).
Referee: C White (England).