Back then Munster had just demolished Sale at Thomond Park, and with the entire side looking completely revitalised thanks to the performances of Barry Murphy and Ian Dowling, Kidney's side were on a high. In a season that had promised so little at the outset, Munster's were suddenly back on course for their Holy Grail. The cup sponsored by the Dutch brewers.

And Leinster? Well on that afternoon a lot of what they'd been attempting that season clicked into place for them but from the outside at least, they'd probably be happy enough with just making the knock-out stages and learning something from their defeat down in Toulouse. With the addition of a couple of beefy brutes to the forwards, they'd be a better side. Next year.

Or so we thought at the time, and so both teams probably thought at the time, but the first Saturday in April has changed the perception of where the symmetry between the two provinces lies. Years of logic were turned upside down and inside out in the blink of an eye because of two victories of contrasting beauty.

But do things really change that quickly? Can the improvement of one side and the supposed deterioration of another happen in the space of two months? Two months when neither side really properly played together. Can it really have changed?

The perceived wisdom now is that Leinster are favourites for the game and Munster, well, aren't. It's a two horse race after all; one side has to have the tip of their nose just in front of the nostrils of the other.

And so, why not Leinster?

They've played some genuinely scintillating and thoughtful rugby in those big games they've been judged upon the away victories over both Bath and Toulouse. They appeared to have been well coached and not coached at all in those fixtures, a neat little trick of perception which means they know exactly what they're doing. They're like the young fella who spends half an hour fixing his hair so that it looks like he never touched it.

But like that tousle-haired young buck, they still leave you wondering about their true substance, no matter how convinced you've been watching their games against Bath and Toulouse. And re-watching them.

Their back play and general continuity is as advanced as anything in European club, or indeed international, rugby and there are few better sights in the game than seeing Felipe Contepomi take a tap penalty and watching what happens next.

But you still have to wonder what'll happen to them if their penchant for taking risks lands them in more trouble than they can work their way out of. If the speculation doesn't lead to accumulation. And the reason we wonder is because it hasn't happened yet, not in any game worthy of note. We don't know how they'll deal with it but most importantly, neither do they.

We know all those things about Munster, you see, but you can understand why they're supposed to be the ones with the ground to make up.

Since Barry Murphy has gone under the knife and had a pair of crutches seemingly surgically attached to his lower arms, that little sprinkle of unpredictability in Munster's play just hasn't been visible.

And we've all been watching.

They inched their way past Perpignan in a performance they should have been given more credit for, but it was typical Munster stuff; raw aggression allied to superb line-out play and the boot of Ronan O'Gara. They played to script, to everything that's expected of them but they didn't play the game at pace and if there's one thing that has set Munster up for all their big wins over the years, it's been the speed they've played the game at. They did it against Edinburgh last weekend and destroyed them. They'll need to do it again.

So while many critics are setting this one up as the battle between whoever plays better, the Leinster backs or the Munster forwards (or for that matter, the Leinster forwards or the Munster backs), that's all too simplistic a call on things. Rugby is changing and while the game's snobs out there will say that matches are won up front and the fancy boys out wide decide by how much, it's not all that simple anymore.

Leinster have proved that as much as anybody this season.

In their past three games against Toulouse, Borders and Llanelli, Leinster have struggled manfully for possession but they've still managed to score at least 50 per cent of their tries in all three games off first phase. And if you can score 50 per cent of your tries of first phase, you don't need all that much possession to win games.

Munster have proved the corollary of that point. They've owned truckloads of ball against Perpignan, the Dragons and Edinburgh but it was only in that final game they were able to do anything useful with it. In many ways, the dynamics of the game have been overturned in recent times and with that in mind the line-out has became the sport's most crucial component.

Most top-level games now average somewhere in the region of 30-odd line-outs per game and Munster are kings in this department, not only in this particular game, but perhaps in all of European club rugby. They just don't cough up much ball . . . maybe one or two per game if they mix up a couple of calls . . . and when the opposition hooker has the ball, they're always aggressive in looking for the steal. Leinster, on the other hand, showed last week that while their work out of touch can be as good as Munster's on any given day, they're also prone to the odd breakdown.

Michael Cheika attempted to downplay the Llanelli first-half meltdown this week but you can be sure he's more worried than anyone about the situation. Munster will attack them here all day and it's going to take a supreme Leinster effort to ensure that they come out of this particular area with something approaching parity. That and a couple of other areas will be key.

The battle between the respective number sevens, Keith Gleeson and David Wallace, is not only going to be fascinating, it's going to be critical to both side's chances. And of course, whoever manages to get a better hold on the game at out-half between Felipe Contepomi and Ronan O'Gara, will go a long way to ensuring they and their team are winners on the day.

All of which brings us to who's going to actually win this afternoon's game and critically, whether the new order that's supposedly come about since the quarter-final weekend has any real truth or merit to it.

Taking a look at both provinces in their last three games is instructive. Leinster, as we've already said, have played Toulouse, the Borders and Llanelli. Played three won three. Munster, meanwhile, came up against Perpignan, the Dragons and Edinburgh and lost to the Welsh side.

One up to Leinster, you might think. But if you take another look at the games, there's a bit more to it. In those three games Leinster have scored 13 tries to Munster's eight, Cheika's side on top again, but it's the points differential in those games that's most interesting. In all Leinster have scored 106 points but conceded an extremely high tally of 86, while Munster have scored 72 and conceded just 48.

All totted up, that gives Munster a point's difference tally of plus 24, with Leinster's standing at plus 20. So what, you might say. But there is a point to this. While everybody's been impressed with Cheika's side lately, Kidney's supposed underperforming outfit have been marginally more efficient on the scoreboard, even if they have lost a game more. They don't score as much but they concede significantly less. In what promises to be a close game, efficiency on the scoreboard, particularly in the points conceded column, will be critical.

The thing is we've all seen what Leinster can do over the past couple of months but we have to take what Munster are capable of on trust. But it's a big day at Lansdowne road today. The biggest. And we trust Munster the most.