Once more unto the breach dear fiends. When Clermont and Leinster collide, it's personal. And it's physical.
And it usually defines each team's European campaign.
The French giants would arguably already have been crowned champions in recent times were it not for the unstoppable force that is the three-time champions, with whom they have engaged in one of the most pulsating club rivalries of modern times. And, of course, were it not for an unforgettable Brock James meltdown in an RDS quarter-final three seasons back.
Not to mention, too, the 123rd tackle of an incredible semi-final in Bordeaux last May when Gordon D'Arcy's last-ditch attempt ensured Clermont and Wesley Fofana were denied a breathtaking win.
This Sunday, Leinster will need all their available armoury as they head to fortress Stade Marcel Michelin, the forbidding home ground where no team in an astonishing 50 attempts has pilfered a win against the hosts.
Boarding the flight with a fully equipped Tullow Tank will be a vital boost to their chances after Sean O'Brien successfully endured two hours of game-time since returning from complicated hip surgery.
"It's not a lot of game time, but he's put in a massive amount of work to come back from his injury and to now be playing through games," says assistant coach Jono Gibbes of his ball-carrying talisman. "The medical people have managed his workload really well and they're confident that he's in good nick.
"He's got a good engine and he's got a big heart so they are two massive attributes you need. I think he's building back into it. It's a game and a half so it's too soon for him to be right there. But I think he's building positively.
"He's a positive guy anyway – just his sheer presence at training, he lifts people and he's a robust carrier so physically there's some real positives."
This is a traditionally pivotal time in the Heineken Cup, particularly this season, with the top two clubs in five of the six pools going head-to-head – Ulster v Northampton and Munster v Saracens will also be key in deciding knockout berths during the next fortnight.
Although Leinster lead the series between these two clubs 5-1, dating back to 2002, Clermont are in vintage form in Europe, as they are the only club with the maximum 10 points after two games.
After resting a clutch of their star-studded squad in the 30-22 domestic defeat away to Toulouse – albeit they finished strongly following James' introduction from the bench – coach Vern Cotter warned his side they need to tighten up in defence.
"It will be necessary that we are asking the right questions before hosting Leinster as we committed defensive mistakes that we should not repeat against the best team in Europe," said Kiwi Cotter, who dovetailed with Leinster coach Joe Schmidt in leading the side to a cherished Top 14 title in 2010.
O'Brien and Jonathan Sexton were replaced halfway through Leinster's facile victory against Zebre as a precaution, but both Ireland internationals trained fully in UCD yesterday, alongside Damian Browne, who suffered a cut above his right eye on Saturday.
Already without Brian O'Driscoll, Dave Kearney (quad) and Eoin O'Malley, slowly recuperating from cruciate knee damage, are Leinster's main worries. "We'll expect to have greater clarity after giving them a bit of time and we'll see where they're at come the end of the week," added Gibbes.
Jamie Heaslip, the competition's leading tackler (29) this season, and Richardt Strauss, who were rested following their recent international exertions, also committed fully in yesterday's session.
Meanwhile, on a further weekend of milestones, out-half Sexton's next appearance will be his 100th for his home province.
Asked if Leinster could replicate last year's semi-final intensity at this early stage of the season, Gibbes was insistent.
"Absolutely, I have no doubt. We're not going in there naively. We know what it's going to be like. We've good experience from players who have been there a couple of years ago.
"We have guys who were there in the semi-final against them last year.
"We have Joe's knowledge of them. We've played these guys a few times and we know what we're going to get.
"Our preparation has to reflect that and I'm sure it will."