It was a grey day in Dublin, a blank canvas awaiting a few vivid splashes of colour. And what a vision duly unfolded. This was as sensationally good a finale as the tournament has seen and, by the end, it was all yellow. For the second year in succession La Rochelle hoisted the Champions Cup, while Leinster’s drive for a record-equalling fifth title was denied.

Great games of rugby are not always reserved for the greatest of stages but this one had pretty much everything. Expectations had been high but they were comfortably exceeded in the first 40 minutes alone. At 17-0 down inside the first dozen minutes, there seemed only one winner. Instead La Rochelle engineered one of the all-time great comebacks, clinched with a 72nd-minute close-range try from their vast replacement prop Georges-Henri Colombe.

Related: Leinster 26-27 La Rochelle: Champions Cup rugby union final – live reaction

For Leinster, who had Michael Ala’alatoa sent off for poleaxing Colombe in the 78th minute, it will be beyond painful to fall just short yet again. They have rarely started a big game better and still it was not quite enough. Not for the first time they were worn down by their opponents’ close quartersclose-quarters power and ability to vary their game, not to mention the guile of their old foe Ronan O’Gara. “The players showed serious resolve and I think were worthy champions,” said O’Gara. “We’re becoming a special team but this is only the beginning.”

The upshot is that Leinster have once more been thwarted on the threshold of true greatness. Just one Champions Cup title in 11 seasons, given their domestic pre-eminence and talent pipeline, is a paltry return and fewer than La Rochelle have claimed inside 12 months. Given they were fielding virtually the entire Ireland team, it also has psychological implications for this autumn’s World Cup.

How different everything looked in the first quarter. Not only did Leinster start brilliantly, they were thinking smart as well. Barely 40 seconds had elapsed when a cleverly disguised lineout move had the ball thrown to Jack Conan. He surged into a huge gap at the front of the La Rochelle lineout that long hours of intensive video analysis had clearly identified. An offload to the supporting Dan Sheehan and – boom – Leinster were already in the box seat.

Even better was to follow. A clever switch of play gave James Lowe the angle to drill a spectacular left-footed 50:22 kick into the corner. Again Leinster executed brilliantly, sucking in the defence before going wide right where Jimmy O’Brien had the time and space required to make the corner. Ross Byrne’s conversion bounced off the upright but 12-0 up after six minutes was beyond even the most fervid local imaginations.

And then came act three. Leinster were performing like men possessed, barely giving La Rochelle time to think let alone build a few phases. A quick tap from Jamison Gibson-Park further raised the tempo and his opposite number, Tawera Kerr-Barlow, felt compelled to tug him back, earning himself a yellow card. Amid the temporary French panic, Leinster surged forward again and Gibson-Park’s long ball put Sheehan over for his second try to make it 17-0 with 12 minutes gone. Was the scrum-half’s pass forward? There was no time available for lengthy contemplation.

La Rochelle, even with 14 players, simply had to find some kind of response. With O’Gara in charge, the only certainty was that it would come at some stage and, soon enough, the fightback unfolded. The gameplan had been to rattle Leinster physically and put them on the back foot. The only snag was they had not had a chance to put it into action. Now, belatedly, their big men poured forward and the boulder-sized Jonathan Danty sat down Garry Ringrose, of all people, to put his team on the board.

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Byrne’s boot, even so, pushed Leinster back out into a 23-7 lead only for La Rochelle’s midfield enforcers to come knocking again. Another blast from Uini Atonio established some front footfront-foot momentum before a nicely timed pass from Antoine Hastoy put the strong-running Samoan centre UJ Seuteni over. Hastoy’s conversion made it 23-14 and the half-time whistle, almost unbelievably, came as a slight relief to the blue-clad sections of the crowd.

The stage was set for the mother of all second halves. Soon enough Seuteni was rampaging down the middle of the field and, while he was eventually dragged down, La Rochelle were swiftly rewarded with another Hastoy penalty. The game had entered a more cat and mouse stage, albeit one involving a big cat and a positively huge rodent.

With half an hour left it was still 26-20 to Leinster but Tadhg Furlong had left the fray and their physical examination was only just beginning. By now every turnover was being greeted as if it were the decisive act in a World Cup final but, ultimately, it was Colombe who settled it. If it is a France v Ireland finale in Paris this autumn, another classic awaits.