March 19 was a pretty special day in Irish sport. Lest you need reminding, England won the Six Nations but we denied them the Grand Slam by winning the match -- with quite a bit to spare. Given the week, it was a great day to be Irish.
The English took their disappointment with great humility -- as they always do in such circumstances. But that was then and this is now.
It may be just three weeks ago but already it is history. And yet there are some trying to link the Leicester five (Tom Croft, Louis Deacon, Dan Cole, Ben Youngs and Toby Flood) and Leinster nine (Brian O'Driscoll, Gordon D'Arcy, Eoin Reddan, Cian Healy, Mike Ross, Sean O'Brien, Jamie Heaslip, Leo Cullen and Jonny Sexton) who played in that momentous match.
Their theory is that this evening's match presents the visitors with an opportunity to exorcise the Aviva ghost, while, for the Leinster players, the psychological advantage gained while wearing green will somehow see them home again. Get a grip.
What transpired on March 19 will have no bearing whatsoever on this game, irrespective of how many of the same personnel are involved again now.
If there is one Leinster player thinking about what happened when last he ran out in the Aviva, then he shouldn't be out there today. Equally, if there is a Tiger motivated by putting right some type of wrong while wearing white, then he too is in a bad place ahead of this Heineken Cup showdown.
So can we put that theory to rest for the balderdash it so clearly is?
Can we also banish the myth that this is Leinster's all-singing, all-dancing backs against Leicester's uncompromising, gnarly old pack?
Focus instead on real rugby embracing two complete squads who can play it either way. Each takes great pride in its defence yet both sides' back divisions have the power, potential, experience and ball-handling ability to make the most of any line break.
No side has played against Leicester more often in the Heineken Cup than Leinster, and no team has beaten them more -- the record stands at five wins apiece from the 10 games between them in the competition.
Nor is this a purely Welford Road machine. Richard Cockerill has developed a bulldog spirit whereby, home or away, the Leicester aura borders on a sense of invincibility.
Bear in mind that in 1996 and 2005 the Tigers came to Lansdowne and won. In '05, much like now, they came through as one of the best-placed runners-up and then hammered a Leinster team seeded No 1 following a 100pc Pool record.
But what has gone is history and of little relevance to today.
Fittingly, it has been former Tiger Leo Cullen who has brought some semblance of sobriety to the build-up by way of his pertinent references to "old school".
Cullen, along with Shane Jennings, who also spent time at Leicester, knows intimately how they prepare with every yard of ground and point posted earned the hard way.
Despite defeat at the death, last week's run-out in Limerick -- particularly the second half -- could hardly have been better timed, with Munster reverting to type. Leicester, unashamedly, operate off the same template but with greater guile in midfield and potency down the outside channels.
There are individual and unit match-ups all over the field to savour, with the half-back head-to-head particularly appealing.
Were a Lions party heading off next month, Youngs, Flood and Sexton would be shoo-ins for the party, with Reddan in with a very good shout. All four are cool operators under pressure.
The fact that the Irish pair got the better of the tactical battle when they last met is irrelevant. This is a different game. The half-backs' influence depends on the quality of ball they are presented with, and while the Irish eight outpsyched and outmuscled the English forwards, you cannot envisage anything remotely close to that developing up front this evening.
The greatest threat to Leinster is Youngs. He may be only 21, but this guy (son of ex-England international Nick) is the business. He is already pretty much the complete scrum-half and by some way the outstanding No 9 in the four 'Home' nations.
Flood, too, has come on leaps and bounds since arriving at Welford Road from Newcastle. His ability to find space and exploit the gap for others running angled lines has added a different dimension to Leicester's attacking game.
But Reddan and Sexton also operate a high-tempo attack. They, too, can mix and match, with Sexton more adept than Flood in kicking out of hand. Quite where this fallacy developed that Sexton runs whereas Ronan O'Gara kicks is beyond me.
I feel Healy and Ross can match Cole and Boris Stankovich at scrum time, and possession out of touch will break even, so it will be the use of possession through the halves that will determine everything.
Both Flood and Sexton operate on the heads-up principle, with both well capable of reading 'springers' in the opposition defence. It makes for a fascinating tactical duel.
And with Reddan and Youngs both adept at sniping and attracting the defensive focus of the opposition back-rows, space and time could well open up a bit further out.
It has all the relevant ingredients for a corker. Put any English revenge theories to bed. They simply don't apply. This is about Leinster v Leicester, the best of Irish against the best of English for the right to a home semi-final against Biarritz or Toulouse.
It was mapped this way for Leinster in '03 (with a Dublin final to follow) and we all know what Perpignan did back then.
Yet home advantage does matter. With a full house guaranteed, the crowd could tilt it Leinster's way, but the hosts will take nothing for granted. Both teams have come too far to underperform now.
Take it as read, they will each deliver, but on the basis that last week's experience brought Joe Schmidt's side back to earth with a bang, they are at the peak of their all-consuming powers. The appetite for a repeat of '09 is back.
Take Leinster but, for the second week running, keep your defibrillator to hand.