As high-stakes games go, this will certainly be the biggest of Ireland's three-Test tour of the Americas. There will be an understandable note of post-World Cup triumphalism and expectancy amongst the capacity home crowd, but from an Irish perspective there will also be a whiff of vengeance in the air. To call this a friendly would be a misnomer.

For sure, there's no bad blood as such between the two, and only five of Ireland's starting team which saw their World Cup hopes subside in Lens eight months ago are in action.

A lot of water has passed under the bridge since then, and for two-thirds of the team Lens is well out of focus. Even so, a victory would provide some measure of consolation and would affirm that the revival in Irish rugby is very much for real.

Most of all, it would break a depressing sequence of Saturday defeats on tour for Irish rugby over the last couple of decades. Indeed, one has to go back to 1979 and the Ollie Campbell-inspired 2-0 series win over the Wallabies for Ireland's last Test win of note abroad.

And considering all the harrowing Saturday defeats to the Queenslands, New South Waleses, Aucklands and Western Provinces of this rugby world, this would probably be the most significant Saturday win on tour since then. It would also set up the remainder of the tour nicely, and strike a significant psychological blow for this team were they to take such a noted scalp without their attacking totem, Brian O'Driscoll, not to mention the missing cutting edge of Denis Hickie.

Of course, their absence only lengthens the odds against Ireland, for the Pumas have to be favourites given they won the most recent meeting on neutral territory. Over two-thirds of that team link arms again, and at home they're a different proposition altogether.

You point to the head, suggest it's one of those mercurial Latin things and even local rugby men just shrug and say si.

With interest in Argentinian rugby never more acute, and a partisan 25,000 crowd liable to sound like twice that number, the Pumas will be as high emotionally as ever in their own capital. Traditionally, it's regarded as a fearsome venue for visitors.

They beat England here three years ago 33-13, they beat Scotland in both Tests here six years ago, and, as Warren Gatland remembers on his last tour with New Zealand, they pushed the All Blacks close in 1991. And they beat the Wallabies on their last visit here three years ago.

An in-form Welsh team might well have been beaten last summer, and Argentina are far less likely to chuck away a 20-point lead as they did then after the confidence generated by reaching the last eight of the World Cup.

Their former New Zealand manager, Alex Wyllie, repeatedly said that self-confidence was the biggest missing ingredient in the Puma make-up, and they'll have more of that than ever to marry with their innate footballing ability.

Discipline will be a key factor. Referee Andre Watson will be a key (non-) player. Sinbinning would not be a surprise, nor even a red card come to think of it. The South African can be expected to adhere strictly to the IRB guidelines when he applies the law which penalises passes made behind decoy runners when they are close to the gainline.

The Pumas will seek to take Ireland on up front. The installation of Agustin Pichot as a once-off captain in the absence of Lisandro Arbizu only underlines his playmaking role for the blue and whites.

Given not too much is likely to go beyond the slightly ponderous but prolific and prodigious Gonzalo Quesada, especially without Arbizu (the Pumas' catalyst when they broke free in the last quarter in Lens), Pichot will probably launch the target runners up front repeatedly.

Even if Ireland ape Munster in absorbing pressure, the Pumas might again be content to play for position and allow the metronomic Quesada to pile up the three-pointers.

It will be akin to Northampton's approach against Munster, with even two of the front-row men included: Federico Mendez, who has much to play for on his return and in convincing new coach Marcielo Loffreda, and Martin Scelzo. Their role is huge, for the Pumas' renowned scrum is more than just a status symbol. They will target the Irish scrum and John Hayes' technique will again come under scrutiny. Ireland, too, have concentrated more heavily on this set-piece in their two training sessions.

The fear would be that Ireland might not get enough primary possession. If they do, then they appear more likely to have a cut out wide than their hosts.

The Maggs-Henderson midfield ticket brings different strengths and both are in prime nick, while Mike Mullins is a weapon off the bench. Peter McKenna's pace and angles of running when hitting the line could be a weapon, while David Wallace is playing the best rugby of his life so far and deserves his chance as the best option to Dawson.

But whether Ireland can be as effective in this has they have been of late without O'Driscoll and Hickie, not to mention the absence of Kieron Dawson's presence at the breakdown, is unproven.

Were they then to attack along narrower confines, the suspicion lurks that they would be playing into the Pumas' hands. Shades of Lens then perhaps, with home advantage swaying things more toward the Pumas in a tight-game with tries at a premium.

A significant mental difference this time, however, is that with home advantage comes the additional pressure of having to win. Ireland felt that pressure in the World Cup, panicked and buckled after being on top for over an hour. Now the heat is on Argentina, who are bound to be a little rusty as a unit if less disrupted by injuries.

The match kicks off at 3.40 p.m. local time (7.40 p.m. Irish). It's an awful shame that RTE aren't televising the game. It's more meaningful than most non-competitive Tests, and certainly more so than last Sunday's game against the Barbarians. It has recent significance as well as a present and future significance.

Were Ireland at full strength, with the more proven triumvirate of the get-out-of-jail card in midfield (O'Driscoll), the cutting edge on the wing (Hickie) and the genuine openside (Dawson), Ireland would be better armed to take on Argentina where they are more likely to be hurt, at a high tempo and out wide.

Were this game coming at the end of the tour and Ireland had fewer disruptions, they'd have a real chance. They still do, and all of this would make a win even more creditable.