Had this unique occasion been held at the conclusion of the Celtic League pool stages then it's hard not to think the sense of occasion would have been altogether greater. Back in the autumn, with both provinces on a roll in this competition, a one-off semi-final between Munster and Ulster in Lansdowne Road would have generated bigger interest and hence attracted a bigger crowd.

Instead estimates from both provinces suggest this semi-final will do well to lure 10,000 people. This is traditionally a Christmas holiday weekend for the farming community and trains from Munster were sold out before this fixture emerged. The recent spate of international weekends have probably diluted the appeal of day trips to Dublin as well.

As things stand, Munster have only sold about 1,000 tickets and while cash at the turnstiles makes advance ticket buying unnecessary, the red army is more likely to be a battalion relatively speaking today. Ulster estimate their travelling support will be around the 3,000 mark.

Much then depends on the weather and the passing interest of the non-committed Dublin public, and it does seem a pity that the Celtic League organisers and the IRFU couldn't go with a semi-final double-header today.

In any event, with Munster being comparatively well sated with success these past few seasons, Ulster may have marginally more support today for their first trip to Lansdowne Road since beating Colomiers there in the 1999 European Cup final. Indeed, remembering Dungannon won the AIL final here last season, Lansdowne Road has become something of a happy hunting ground for Ulster sides - especially those inspired by David Humphreys.

For the last few seasons - and especially this season - the general perception, even within Ulster, is that Munster and Leinster are a cut apart, and Munster have beaten Ulster on the last five occasions in which the sides have met. But with Humphreys cutting such a dash lately, Ulster arguably have a better chance to end that sequence than at any other time in the last two seasons.

Furthermore, there's also a suspicion that Munster's Ireland connection especially (today it's one-third of the side) are running on empty a little bit. Collectively, as coach Declan Kidney conceded, they didn't perform particularly well against Llanelli last week (referee Rob Dickson made a bad game worse, unsympathetically contributing to the 84 stoppages).

Munster have, admittedly, won eight games on the spin and from one to 15 they still look the stronger team but Ulster might today benefit slightly from having only Humphreys and Gary Longwell involved in the Irish set-up so far this season. And Humphreys is just playing like a dream, while Andy Ward is revelling in the added responsibility of being official captain.

Of late it seems Ulster only have to get within 40 metres of the opposition posts to pretty much guarantee a score. In 10 games for his province this season, Humphreys has scored a remarkable 182 points. All told, he has scored 226 points from 13 starts this season.

Munster's chances of victory will largely depend on them keeping Humphreys out of the game and out of range as much as possible. Both he and his counterpart in an intriguing outhalf showdown, Ronan O'Gara, are likely to play a territorial game.

There's little doubt that the loss of the influential John Hayes and David Wallace is likely to reduce Munster's chances - the absences of Rob Henderson and James Topping probably cancel each other out. (Jeremy Davidson has been replaced on the Ulster bench by Paddy Johns due to a knee strain). Even so, Munster may just have a potentially decisive edge in the tight five and, if so, no one knows how to turn that screw better than they.

With the sides due to meet again in the interpros toward the end of the month, and then again sometime next year, this is the first of three clashes between them this season. The idea of this game doubling up as an interpro had been discussed but there were a few too many logistical difficulties, not least the matter of who would be the home team this afternoon and would therefore be sacrificing a home interpro. Strictly interpreted by the Celtic League rules, Munster are the "home" side this afternoon as Pool B winners.

More than ever before, and as is the case whenever the provinces run into each other nowadays, there is a huge amount of familiarity between the teams and the players. In their first meeting last season Munster won 21-16 with all their points coming from the boot of O'Gara in a game featuring just one try. Two seasons ago, he kicked 26 points in a 36-19 win which actually only featured three tries.

The game will be refereed by the strict Scottish official Iain Ramage, last seen here when in charge of the Ireland-Samoa match, which supports the fear that this mightn't necessarily flow like honey, and for much of the first hour at least it could well develop into a slog for field position and a kicking duel between O'Gara and Humphreys.

In the heel of the hunt, recent history tells us that Munster are more likely to grind it out but recent evidence suggests we shouldn't be too presumptuous about it.