They have not lost at the Stade Marcel Michelin for more than three years, a sequence of 41 consecutive wins in the Top 14 plus another nine in Europe.
Nobody has beaten them there since Biarritz in November, 2009. Leinster, great believers in the time-honoured theory that there is a first time for everything, go there on Sunday reinforced by a run every bit as unprecedented in Europe as Clermont's is in Le Championnat.
Europe's double champions have played 15 ties (14 wins and one draw, at Montpellier two seasons ago) since their last defeat which just happened to coincide with their last appearance in a city where the Michelin brothers invented the pneumatic tyre. Something is going to have to give on Sunday afternoon.
Clermont head Pool 5, the only team in the competition to have taken the maximum ten points from the first two rounds. They did so by scoring six tries at home against the Scarlets and promptly followed that with six more at Exeter the following week.
Leinster's progress has been unusually prosaic by comparison. The Chiefs from the West Country gave them a serious run for their money on their tournament debut at the RDS in October before losing 9-6 to a trio of Jonny Sexton penalties.
At Llanelli in round two, the holders won thanks to more Sexton goals on top of a solitary try, from Isa Nacewa.
With Ireland's finest yet to hit their straps, Clermont have good cause to be wary. Leinster have beaten them in Michelin-ville even if it was ten years ago but the fact that they knocked them out in the semi-finals last year will be all too fresh in their minds.
Joe Schmidt's team did it on French soil, in Bordeaux where a collective iron will enabled them to survive a late Clermont siege, if only just.
The Dublin return follows seven days later and when the dust settles, a bonus point secured here or denied there may well prove crucial in determining who plays where in the quarter-finals.
The majority of those eight qualifiers last season came from the RaboDirect Pro 12 - Leinster, Cardiff Blues (thrashed 34-3 at the Aviva Stadium in the quarters), Munster, Edinburgh and Ulster, beaten in Europe's first all-Ireland final at Twickenham. This time round, the PRO12 have found it tough going.
Five of their clubs go into the halfway stage of the pool competition in trouble after losing both opening matches. Edinburgh, Benetton Treviso, Zebre, Glasgow Warriors and Cardiff Blues are all in the same predicament.
In a competition where French teams head three of the six pools, Ulster have spearheaded the RaboDirect PRO 12 challenge by jumping three points clear at the top of Pool 4.
After 12 straight wins, the season's only unbeaten club face a severe test of their all-round strength at Northampton on Friday night.
Neither side has been enamoured by recent efforts. Ulster head coach Mark Anscombe sounded distinctly unimpressed with his team's 19-12 win over the Scarlets in Llanelli last Sunday, understandably so, given the depleted state of their Welsh opponents.
As if to make himself perfectly understood, Anscombe talked about 'some dumb rugby' and warned of consequences.
"Some guys had the opportunity to put their hands up for selection," he said. "They didn't take it and will be missing out…"
The New Zealander who took over from Brian McLaughlin at the end of last season suggested that Northampton would be 'pretty confident after seeing our game on television'. If they were, the Saints were certainly not saying so.
On the contrary, skipper Dylan Hartley sounded a similar note of caution after his team's Aviva Premiership win at Sale - 'We are going to have to be better.'
Ulster, knocked out of the quarter-finals by Northampton two seasons ago, know that a 13th straight win will put them halfway towards a home quarter-final.
At least one ex-Northampton player has singled Ulster out as potential champions. Pat Lam, the Samoan back row forward who captained the Saints when they surprised Munster in the 2000 final at Twickenham, believes Ulster have already established themselves as one of the teams to beat.
The Franklin's Gardens event will be followed 24 hours later by another mighty Anglo-Irish duel. Saracens, top of Pool 1 after wins over Edinburgh and Racing Metro, put their reputation on the line against Munster at Thomond Park aware that history is not exactly on their side.
A whole host of English teams have bitten the dust in Limerick. Munster have played English opposition at Thomond on 15 occasions since the early days of the European Cup and won them all with the solitary exception of Leicester in 2006.
Their victims include Saracens, edged out 31-30 in another climactic finale 13 years ago.
Munster edged them out again the last time they met, in the 2008 semi-final at Coventry's Ricoh Stadium. Again,
Sarries went desperately close to toppling a Munster team then only weeks away from regaining the European trophy they won for the first time two years earlier.
Munster may not be as formidable as they were then but Sarries will reserve judgement on that until after their Thomond experience…
63x46.png){kind=logo}