They haven't gone away you know.
After Ronan O'Gara's incredible drop-goal in round one plunged a knife between the shoulder blades of last year's finalists, Northampton Saints face the re-match two months later with an unquenchable thirst for vengeance on their mind.
What killed them on that unforgettable afternoon has ultimately made them stronger -- now terminally wounded in this competition, they will be eager to hamstring Munster's progress by condemning them to an awkward away quarter-final.
And, despite the internecine squabbles this week that have seen Chris Ashton bombed out of the squad as he contemplates next year's £300,000 switch to Saracens -- a one-third salary increase -- Jim Mallinder's men need this one as much as Munster.
They will want to maintain their interest in the Amlin Challenge Cup as a potential route back into the Heineken Cup next season, even if some abacus anoraks have plotted an unlikely scenario whereby they can still qualify.
We don't see that happening, but then few Munster supporters would ever doubt the credibility of any potential miracle.
As Paul O'Connell recalled during the week, when Gloucester visited Limerick all those years ago, revenge was the only thing on Munster minds. History records what happened next.
There will be no miracles today; but then, Munster's progress thus far this season has arguably been the product of a series of minor miracles itself, given their horrendous injury list and their less than impressive contributions behind the scrum.
It is precisely because of their inability to eke out even one more bonus point along the way that leaves them in such a sticky position, despite the fact they were the first team to qualify for the last eight.
Hence, Munster need a sixth successive victory to ensure a quarter-final that would not only be lucrative but, even more vital to their cause, eminently more winnable than if they were to try their luck on the road.
Northampton were the better team at Thomond Park and even this week the sense of injustice still seethes quietly in every pre-match interview; such is the way of an English side who are rarely found lacking in the self-esteem department.
That they lost jarred momentously with an outfit who had strengthened their squad considerably since their fatigued second-half blow-out against Leinster in last May's Millennium Stadium final.
Such was their despair following the perceived injustice -- they still maintain there were two illegal phases amongst the 41 that set O'Gara up for his match-winning kick -- they took their eyes off the ball against Scarlets and lost a glorified game of Sevens against the Welsh outfit.
After two games, in essence, their European hopes were at an end. That they have recovered their composure at home and abroad since reflects their professionalism, albeit the Ashton spat may still have implications.
Should Mallinder maintain his position as favourite to become the next England coach, leaving his country's star winger out of the team indefinitely may count as a black mark against him in some quarters.
Nevertheless, his squad remain galvanised behind him, given that they have all agreed lengthened contracts and his attitude towards individuals such as Roger Wilson and James Downey, two Irish players long expected to return home, hints at a more unified squad than would appear post-Ashton strop. What is clear is the extent of the psychological damage rendered by Munster following that opening-day defeat.
"I think it did affect us," admitted Mallinder. "It was a massive thing for us. We played well in Munster, we didn't get well beaten and it was tremendously disappointing.
"We felt we just didn't quite get the rub of the green and that had a massive influence on this Heineken Cup group. We have accepted that and now we want to go out and prove we can beat Munster. We're disappointed we're not in the Heineken Cup knock-outs because we want to win every single game we can, but the Amlin Challenge Cup is a good competition and we used it as a good springboard a couple of years ago.
"The first game against us and the second game against Castres sum up what this Munster team is all about. They didn't win by much, but they won, and that's what the Heineken Cup is all about.
"They've got the players in their squad who know how to win and it will be a very difficult game.
"We are definitely going into the match with our minds focused very much on getting the win. We have had a good run recently and have some big matches coming up, and want to keep our momentum going."
For his part, and maintaining Munster's tradition of respect for the opposition, coach Tony McGahan is appreciative of the strides that Northampton have made, even if that ultimately won't be enough to maintain their interest in the Heineken Cup.
"They are one of the best sides in Europe and I don't think them not being in the quarter-finals this year dilutes that," he said.
"They have high-quality players in their group and I think that is reflected in the national selection for the English squad. They have a highly sought-after coach who could be a national coach, going forward.
"Who knows, if the result had gone another way we could be sitting here in reversed positions so we have a lot of respect for them and what an excellent side they are."
As expected, with Ashton joining his fellow English team-mates, the injured Courtney Lawes and Tom Wood, on the sidelines, the side may be weakened somewhat.
Then again, Munster's injury woes have undermined their imperious stature of late. Their predictable selection will again rely on the big names -- O'Connell and O'Gara -- to lead from the front.
The odds are not insurmountable and a five-point handicap reflects Munster's durability this season.
Even though the home side are favourites, Munster know they are already qualified so they have a free throw and, with so many people writing them off, this is when they can be at their most dangerous.
Today could be an opportunity for Munster to tell the rest of Europe that they haven't gone away either.
Northampton Saints -- B Foden; J Elliott, G Pisi, J Downey, V Artemyev; R Lamb, L Dickson; S Tonga'uiha, D Hartley (capt), B Mujati; S Manoa, M Sorenson; C Clark, P Dowson, R Wilson. Reps: B Sharman, A Waller, P Doran-Jones, C Day, B Nutley, M Roberts, S Myler, S Armstrong.
Munster -- D Hurley; J Murphy, K Earls, L Mafi, S Zebo; R O'Gara, C Murray; W du Preez, D Varley, B Botha; D O'Callaghan, P O'Connell (capt); D Ryan, P O'Mahony, J Coughlan. Reps: D Fogarty, M Horan, S Archer, M O'Driscoll, D O'Callaghan, T O'Leary, I Keatley, D Barnes.
Ref -- R Poite (France).
Northampton Saints v Munster,
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