Brian O'Driscoll's World Cup Diary: It's a little hard to temper the euphoria of having earned a place in the World Cup quarter-finals after yesterday's victory.

This was our goal, the minimum benchmark that we set out to achieve prior to our arrival in Australia.

We've managed it but only just. The quality of performance left a great deal to be desired, falling somewhere between indifferent and rank. The only thing in those circumstances is to finish on the right side of the scoreline. Winning scrappy, error-ridden matches just about preserves your sanity because to lose means death by a thousand "if only" scenarios.

We didn't hit the heights to which we aspired, didn't play the game we wanted to and certainly didn't execute the gameplan with the precision required. There were, though, mitigating factors. Nerves were definitely a factor, not just on match day but also during the week.

There has been ferocious pressure to exorcise the memories of Lens, to right a wrong in Irish eyes and to maintain an interest in the tournament to boot.

The match four years ago was a monkey on our backs; you couldn't get away from it, it was thrust in your face almost every day in the build-up to the game, not though within the squad. But it was possible to feel the tension and that didn't evaporate because of the pattern the game took.

It was scrappy, with both teams fighting tooth and nail for every ball. The scoreline was tight and that guaranteed that players were loath to take chances. One mistake and you could have been out of the competition. It's funny but when you think back and realise the amount of pressure that players were putting on themselves, never mind what the Argentinians were exerting, it's no surprise that there were frayed nerves.

I thought the pivotal moment of the match was the introduction of Ronan O'Gara. He gave us that belief, metaphorically shook us by the jerseys and breathed a new direction to our patterns. He was quite simply inspirational and a pivotal part of the victory.

The flip side of the coin was the injury (dislocated shoulder) suffered by Quinny (Alan Quinlan). It was, as they say, in a good cause and in fairness he's taken the fact that his World Cup is over extremely well. He is an upbeat sort of person and didn't want to dwell on the negatives of the moment. He scored the try that got us to a World Cup quarter-final.

On a personal level it was another frustrating afternoon with the ball again not really running my way. I was a little disappointed but that tends to be superseded by the team winning. It's always easier to get over personal disappointment after your team has won.

I won't allow myself to get frustrated, just continue to be positive and hope that I finally get the ball I crave. I met my new Leinster team-mate Felipe Contepomi twice yesterday. On the first occasion it was to give him an earful after he had upended Girv (Girvan Dempsey) in the air. He seemed contrite but when his pleas were backed up by Mauricio Reggiardo grabbing me, I decided to pursue a more long-distance conversation.

I spoke to Felipe again after the game and to suggest that he was disappointed would be an understatement. He's a nice guy and I'm looking forward to playing together when we get back to Leinster, although hopefully not in the foreseeable future.

This week has been completely different from the previous periods in building up to our other two games. We're now ensconced in a city-centre hotel, a far cry from our Terrigal base, and there are a lot more Irish fans about. The atmosphere has been fantastic.

It also allowed my midfield partner in crime, Maggsy (Kevin Maggs) - he had a superb game yesterday - to indulge his gun fetish. Surely going to the shooting range Thursday, Friday and Saturday cannot be healthy. God knows, next he'll want to watch Clint Eastwood videos.

People will be critical of how we performed yesterday but I don't believe that will be repeated next week. This match was a huge psychological hurdle - Australia represent an opportunity to have a real cut off one of the best sides in the world.

The players are aware that a repeat of the sort of display we put up yesterday will see us whipped by either the Australians or France, or both.

I honestly believe that the mindset will be different. For now there is an overwhelming desire to chill out and savour the victory if not the performance. A couple of beers with my family, who came out to Australia this week, was the ideal way to unwind.

The squad has gotten over a significant hurdle and we are now charged with taking it on from there. That starts in six days' time against Australia.