Warren Gatland Rugby Analyst: A lot has been written and said about why Ireland have been so off the boil in this World Cup. It makes it even more crucial that the evitable review process by the IRFU is a thorough examination, not just of Eddie O'Sullivan as a coach but the performance of the whole management and the players.

If it is all positive feedback then they can continue with the current set-up. If not change is required.

Everyone must be questioned. It requires a special personality to be given a six-year term as national coach. Not too many men are up to the task. Ten years, well, that requires a master tactician. The IRFU shot themselves in the foot by extending O'Sullivan's contract pre-World Cup. Time will tell if there is an exit strategy.

People will be looking for answers to Ireland's failure in the World Cup. The question about Ronan O'Gara's off-field exposure, O'Sullivan's conservatism and whether the camp lacked harmony are not sufficient excuses given the experience of this group and on the basis of what they have achieved to this point.

This goes deeper still.

One theory could be that they were in camp for too long a period. Over-coaching happens. The Munster and Leinster players looked drained after their European Cup exits after a high-intensity Six Nations. Was there nothing left in the tank? While the coaching structures need re-examination, several players also appear to be surplus to requirements. Denis Hickie has retired, while John Hayes and Malcolm O'Kelly, among others, won't be around for the next World Cup. They should be dispensed with before the Six Nations so the small playing base in Ireland can be best utilised for New Zealand in 2011.

I genuinely thought Ireland were capable of winning this match but I had not counted on Argentina's superior physicality. They utterly dominated the collision areas. Ireland had no response to this power. The maul, which was so reliable six months ago, regularly collapsed, leaving them with two choices: kick for position or move ball on the back foot. As the match ticked on and they required tries this became one option.

Running the ball when your forwards are lying under a heap of bodies becomes an invitation for turnover ball. Argentinian backs were happy to oblige.

As both France and Ireland have discovered, the Puma game plan is relentless. They have a solid maul, set-piece and a near flawless kicking game.

Juan Martin Hernandez is a fullback playing at outhalf so he can challenge his own aerial bombs. Geordan Murphy had a good game but was twice eclipsed in the air by Hernandez.

I don't think O'Gara was looking for touch when kicking ball from hand, rather territory, but this played perfectly into Argentinian hands.

When the All Blacks go to Buenos Aries they bring a simple phase-based approach. Multiple-phase rugby will wear any side down and eventually gaps will appear. This requires a powerful pack. Ireland were unable to enforce their will on the opposing eight.

Several key players struggled to make any impact at this World Cup. Gordon D'Arcy has been anonymous. I didn't see him make a single line break in four games. Paul O'Connell did okay here but he is supposed to be the Irish talisman. He is expected to dominate the lineout. The first throw-in slipped through his hands while he failed to disrupt Argentina's throw. He didn't live up to his massive reputation.

It was interesting to listen to the New Zealand commentary where Grant Fox noted the Irish backline was unable to construct anything of note (bar the tries from a flat ball for O'Driscoll and Murphy off a short lineout). No one was working off the ball to create space. This is a coaching flaw and another area that requires a thorough review.

New Zealand will be content to play France in Cardiff. Having said that, Bernard Laporte has turned things around since they lost to Argentina. There is more cohesion to their play, allied by a new self-belief. It's potentially a great game that France can win.

Argentina should beat Scotland and will be a serious threat to South Africa in the semi-finals. They can make the final because they don't make mistakes. They have a masterful kicking game (three drop goals from Hernandez) and an excellent defence. And real heavyweight power.

Ireland's malaise became apparent during the Georgia game. The failure to get a bonus point meant their tactics had to be altered radically for this encounter. They would have been happy not to take risks and, like Argentina, sit back and build a lead with three-pointers. They were unable to unfurl a plan B.

It's been a great tournament for the less-fancied rugby nations. Tonga, Georgia, Portugal and of course Argentina have all proved what they are capable of if afforded time and preparation.

It's over to the IRB to maintain this momentum. The IRFU have a more daunting challenge ahead.