And any claims they still had as the continent’s kingpins lie in ruins.
The baton which they wrestled from Munster’s arms in Croke Park three years ago was unceremoniously wrenched from their grasp in the Aviva Stadium by a side no longer content with their status as this tournament’s great pretenders.
The significance of performances and results can be over-emphasised in a modern world where headlines and information are bite-sized and instantly disposable but it would be some feat to exaggerate the import of what happened in Dublin on Saturday afternoon.
Consider just some of the facts: this was Leinster’s heaviest home defeat in Europe since 2005; it was their first ever reversal at the Aviva and it was their first time to lose both mid-pool back-to-backs in the 10 years since the concept was introduced.
The three-time champions’ increasing fallibility had been highlighted in these and many other pages for some months so the possibility always existed against a side of Clermont’s class that the cracks would extend into fault lines when push came to shove.
So it proved.
It wasn’t just the fact that there was no Brian O’Driscoll, no Rob Kearney, no Luke Fitzgerald or Kevin McLaughlin. Neither was it merely because others such as Sean O’Brien, Isa Nacewa and Isaac Boss had been asked to hit the ground running in recent weeks after extended injury absences.
It was all that and more besides.
It was the fact that people like Quinn Roux, Eoin O’Malley and Dave Kearney have all spent time in the casualty ward and the combined absences demonstrated once again how thin the line is in Irish rugby between well-stocked and “skeletal”, as Joe Schmidt termed it.
That Leinster were threadbare was apparent from their reliance on Andrew Goodman and Michael Bent on Saturday. Both may yet prove to be welcome additions but neither were star turns at home in New Zealand where they lived and played until last month.
The pity of it is that the province wasn’t able to discover an unearthed gem operating in some second-row somewhere because the failure to adequately replace Nathan Hines since his departure two years ago came back to haunt them here.
Hines was superb, as is his wont whereas Leinster, in the absence of another Brad Thorn lottery win, have had to flog the ageing Leo Cullen and the replacement of Damien Browne with Devin Toner at half-time did nothing to revive their fortunes.
That said, you could pick a thread in almost any line of Leinster’s efforts last weekend and end up unravelling the entire thing. Few emerged in the knowledge that they had bettered the man opposite. Schmidt said they had been outmuscled but it was more than that.
Clermont sought to play the game on their own terms which meant doing so in Leinster’s half and the advantage of such territory was that they profited from the litany of penalties their hosts coughed up thanks to the sublime Morgan Parra who kicked eight of his nine shots at goal.
Leinster actually claimed two penalties more (14 to 12) yet they were of less intrinsic value given they tended to be won in their own half. They scored more tries as well — two to one but it was Clermont’s that turned the game decisively in the favour of the French side.
That it was Wesley Fofana who blew the doors off was somehow fitting given it was the centre’s spill when already over Leinster’s try line that cost Vern Cotter’s men the semi-final in Bordeaux last May and Clermont added to the hurt with Parra’s conversion and a penalty to open the second-half.
Leinster were 22-9 in arrears and down to 14 men after a deserved yellow card for Sean O’Brien with less than half an hour to go and, though they rescued an unlikely bonus point with late tries from Shane Jennings and Fergus McFadden, they will rue the paucity of their general execution for a second straight week.
It is that which will hurt them most. For all their injury and personnel issues, the province was lacking in the basics. They spilled ball in the tackle, they got turned over repeatedly, got stuffed in the scrum, bettered at the ruck and missed nine tackles. None of that is what we have come to expect from them. Regrets are to be expected but there will be recognition, too, that they were undone by a Clermont team that has always possessed size, power, pace and an abundance of natural ability but which has now put to bed any lingering suspicions as to their mental strength.
It would be a shock not to see them back in Dublin next May.
LEINSTER: I Madigan; F McFadden, G D’Arcy, A Goodman, I Nacewa; J Sexton, E Reddan; H Van der Merwe, R Strauss, M Ross, L Cullen, D Browne, S O’Brien, S Jennings, J Heaslip.
Replacements: S Cronin for Strauss (13); D Toner for Browne (40); D Kearney for Nacewa (59); M Bent for Ross (62); I Boss for Reddan (60); J Murphy for Jennings (68).
ASM Clermont Auvergne: L Byrne; S Sivivatu, A Rougerie, W Fofana, N Nalaga; B James, M Parra; R Chaume, B Kayser, D Zirakashvili, J Cudmore, N Hines, J Bonnaire, J Bardy, D Chouly.
Replacements: R King for Byrne (37); V Debaty for Chaume (60); D Kotze for Zirakashvili (69); T Paolo for Kayser (70); L Jacquet for Hines (75).
Referee: W Barnes (England).