Chris Cusiter Scotland scrum-half

Our primary aim in this World Cup was to reach the quarter-finals - but now we are here, it would be a massive anti-climax to lose.

This is a huge opportunity for Scotland to equal what happened in 1991 and get to the semi-finals and it would be hugely disappointing if we fell short.

Cusiter has had to be content with a place on the Scotland bench

We know that, in Argentina, we are playing one of the form teams of the tournament so far.

I was watching the news and a big football match in Argentina has changed kick-off time so people can watch the rugby - and that is great for the game over there.

I'm sure the players and everyone involved are delighted about that and they have been playing very well up to this stage.

I think teams would always give the Pumas respect because they are very tough to beat, but they have got themselves to a new level now.

They beat France in the opening match and won against Ireland relatively comfortably in the end - they seem to have raised their performance throughout the World Cup.

I do not think they will change a whole lot of what they have done so far, so we possibly know what to expect of them in the Stade de France on Sunday.

But they are very effective in what they do and we have to work out a way to stop them, rather than trying to figure out how they will come at us.

There is lots of talk about how motivated Argentina are for various reasons, but I think that does a disservice to our motivation.

We don't want to get knocked out and for people to say the last eight was as good as we were ever going to do at this competition.

Sunday is no longer a mustn't-lose game, it is a must-win game - and that brings with it a slightly different mentality

We are not thinking that way at all, we are seeing it as a great opportunity to go a step further and surprise a few people.

From our point of view, we will be looking to come up with a better performance than we have produced so far.

That is not to say we have not played well in parts of games and in retrospect I think the 56-10 win over Portugal was a good result considering how well they played against Italy and Romania.

But now it is the quarter-finals and we know we are going to have to step up and play better than we have so far, even though we have kept on improving.

The 18-16 win over Italy was probably as high-pressure a game as we have had for a long time. It was nerve-racking for everyone, but what we had to do was win and we managed to do that.

The situation is different this weekend. It is still high pressure, but it is no longer a mustn't-lose game, it is a must-win game and that brings with it a slightly different mentality.

Our defence has been playing well up to this stage, we have placed a lot of emphasis on that and tried to make it hard for teams to score against us.

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We will have to be rock solid again on Sunday and deal with whatever they throw at us.

We would like to cause them some problems and win the game by scoring some tries instead of kicking goals, but you play what is in front of you and, when the rain came down against Italy in St Etienne, it became a kicking battle and we adapted well.

Chris Paterson kicked the points and he was fantastic, he has got a terrific temperament.

He seems so relaxed when he steps up to take a kick, almost as if he is completely separate from everyone else. He does not feel the pressure other people feel and to have that weapon in your team is unbelievable.

The opposition know that if they concede a penalty in their own half then it is likely to be converted and that can have benefits for the rest of the attack too.

As for myself, it is disappointing to be on the bench but rugby is a squad game and we have got a great spirit within the squad.

There are no factions and no-one is disillusioned - everyone knows their place and has accepted it. Mike Blair has been playing well in my position and we have done well enough to reach the last eight.

I am pleased to be part of the squad and hopefully I am about to be involved in something special - that would make up for not playing week-in, week-out.