Caught your breath yet? Rendering superlatives redundant, this duo clashed like boxing heavyweights from a bygone era. Leinster were the last men standing. Just.
Try as Clermont might, they just could not land the knockout blow in the game's tension-filled dying, breathless moments. Leinster may have been on the ropes, but they had done enough to eke out the win. And that is all that matters.
The merits of their victory should be viewed through the prism of the defeated and deflated opposition; Clermont are one of the great sides in Europe and it needed some performance to surpass them. Leinster were surely the only side capable of doing so.
In truly one of the epic semi-finals of the Heineken Cup era, Leinster squeezed through by a short head in a thrilling encounter suffused with such drama and tension, it was often difficult to keep one's emotions in check.
A first all-Irish final now awaits in Twickenham on May 19, as Leinster joust with Ulster in a bid to become only the second side in European history to complete back-to-back titles.
Connacht, too, will celebrate, as the guaranteed Irish winner ensures the westerners' passage to the big table for the second successive season.
An inter-provincial derby will ask different questions of Joe Schmidt's all-conquering side. Nothing can have prepared them better than this overtly physical and mental challenge.
And yet mere inches denied the resourceful Clermont side a place in the final, when Wesley Fofana momentarily lost control of the ball when it seemed easier to score with just 111 seconds of game time left.
Yet still they pressed as the game shifted into overtime, forcing a penalty at the final scrum of the game only to falter at the coalface of incredibly brave Leinster defence, Sean O'Brien emerging triumphantly with the final, defiant seizure of the ball to signal delirium amongst the travelling band of noisy Leinster supporters.
Leinster didn't always play well, at times they weren't allowed to. Semi-finals are about survival, though. Leinster's survival instincts are currently unsurpassed.
From the stellar strike provided by Cian Healy's 42nd-minute try, conceived by Jonny Sexton in the dressing-room and superbly executed just moments later, the psychological balance of this enthralling tie lurched towards Leinster as they transformed a flattering six-point half-time deficit into a one-point lead, increased to four by the 47th minute thanks to a brilliant long-range Rob Kearney drop-goal.
Clermont, denied an eighth time in Europe by an Irish side, were forced to chase the game and simply ran out of gas. Leinster, puffing heavily, were better resourced in mind and body. And limitless spirit.
Leinster started like an express train and were immediately into their attacking groove, with Kearney and Isa Nacewa linking superbly on the right wing to such an effect that when Julien Malziue left early with an injury, it might well have been caused by dizziness.
They were also dominant on the floor, winning four breakdown penalties, with Richardt Strauss and O'Brien excelling on the ground skirmishes as Wayne Barnes whistled against the Clermont players to their obvious frustration.
The set-piece was the key determining factor in Leinster's inability to build upon their bright start and that also allowed Clermont to edge into a position of clear dominance by half-time.
In effect, they could have been 15-3 up at half-time, Sitiveni Sivivatu gifting Leinster a three-pointer after impeding Nacewa from Kearney's poor garryowen, while they were also en route to a five-metre scrum penalty before Jamie Heaslip rescued Leinster.
As it was, a 12-6 interval lead scarcely reflected Clermont's clear edge at the set-piece and wonderful off-loading game, with Sivivatu prominent throughout. Three lost line-outs, as well as the clear difficulties being experienced at scrum time, undermined Leinster's bright opening.
The sides had exchanged early penalties but Leinster offered more threat in attack, while Aurelien Rougerie, stopped once with thunderous force by Brian O'Driscoll, was just one of the Clermont backs unable to pierce the initial blue wall of defence.
Clermont were able to cut Leinster apart at times, with Sivivatu showing Heaslip and Isaac Boss a clean pair of heels with a blistering touchline sprint, but they were undermined by sloppy breakdown work, as well as great Blues technique.
Leo Cullen should have been binned in the 23rd minute for hitting out at Lionel Faure; his side won a penalty at the ensuing scrum to compound the sense of grievance amongst the cacophonous Clermont crowd. Clermont edged ahead on 32 minutes after their first significant success on the ground but, even when Brock James sauntered though a trio of forwards, a breakdown penalty undid his side's momentum.
When Sivivatu's nudge on Nacewa gifted Leinster a 34th-minute leveller, the away side would have been happy with their opening declaration of intent, until a sloppy six-minute period before half-time undid all their hard work.
Healy was the central figure in Leinster's mini-implosion in the three minutes before the break, just as he would be crucial to his side's rehabilitation in the three minutes after it. Firstly, he was pinged as Barnes began to slowly alter his perception of the breakdown exchanges, allowing James to steer his side's noses in front.
Then, a wild attempted offload forced Gordon D'Arcy to needlessly knock-on and, from the scrum, Clermont got the advantage and James made it 12-6 at the break.
Leinster were rehabilitated after the interval. An inside ball from Strauss set Kearney off on another break; Healy's support ensured the move would end with seven points. Kearney's drop goal in the 47th minute pushed Leinster to 16-12 and the tenor of the game shifted. Now Clermont were chasing and Leinster were willing to defend when required, without ignoring the potential for attack.
James skewed a penalty wide but reduced the margin to the minimum in the 53rd minute; Sexton then restored the four-point lead in the 62nd minute before he was denied by the TMO when a three-pointer attempt flew over the top of the posts.
"Some you win, some you lose," said a relieved Joe Schmidt, reflecting on the two decisive TMO decisions.
Leinster have become used to winning. It will be some feat to interrupt such a forbiddingly familiar habit.
Clermont Auvergne -- L Byrne (R King 20); S Sivivatu, A Rougerie (capt), W Fofana, J Malzieu (J Buttin 13); B James, M Parra; L Faure (V Debaty 48), B Kayser (T Paulo 63), D Zirakashvili (D Kotze 58), J Cudmore, N Hines (J Pierre 56), J Bonnaire (E Vermeulen 60-67), A Lapandry, E Vermeulen (J Bardy 55).
Leinster -- R Kearney; I Nacewa, B O'Driscoll, G D'Arcy, L Fitzgerald (F McFadden 63); J Sexton, I Boss (E Reddan 53); C Healy (H Van der Merwe 55), R Strauss (S Cronin 63), M Ross, L Cullen (capt), B Thorn, S O'Brien, S Jennings (K McLaughlin 63), J Heaslip.
REF -- W Barnes (England).