Hansen said yesterday the side had learnt lessons from all the World Cups, going right back to the first one, the All Blacks' only victory at the tournament, in 1987.
"One of the lessons we have learned is we just have to concentrate and get excited about this weekend," Hansen said.
"This is the biggest test of the year. If we do not win it then we are on the way home. So that brings a whole lot of things into play. Argentina will be a physical pack but we expect that. It is a test match.
"Every side is going to take a step up. You have to because if you don't then you're on your way home and that is not a great feeling is it?"
Hansen said the All Blacks were not even looking at a possible semifinal the following weekend.
Four years ago, the All Blacks rested players and were not totally focused on the job, and went out to France in Cardiff in the quarterfinals.
It is hard seeing that happening again on Sunday, with Hansen and the rest of the management team keeping their feet planted firmly on the ground.
Zac Guildford is the only player unavailable for selection on Sunday, after he pulled his hamstring at training on Wednesday.
Hansen said captain Richie McCaw was managing his foot injury, as he had all year, but would be available to play against Argentina.
"As long as we are still in the tournament then we are confident he will be available to play."
If the injury was causing long-term damage, McCaw would not be risked, Hansen said.
Because of the position he played, McCaw did not train much at the start of the week.
Every player was playing in pain to some degree, and that just had to be managed.
Hansen had a dig at administrators who kept backing up players year after year with exhaustive seasons, which was leading to injuries.
"It's not just this year [having injuries]. It continues to happen. You look at league, where players get 16 weeks to get rid of niggles and have a proper pre-season. In rugby union it is four to five weeks.
"We need a global season. The only people who can do that are the IRB. People have got to be prepared to say our players need looking after."
Northern hemisphere countries were also feeling the effects of a rigorous playing schedule but he said the biggest difference between the two regions was the travelling distance was much shorter in the northern hemisphere.
Hansen said the All Blacks had recovered well from the loss of star playmaker Dan Carter, who limped out of the tournament in the weekend with a groin injury.
Carter was a class player, but his absence gave an opportunity to others, Hansen said.
"We have got a very competitive squad with very, very good players. It gives the opportunity to the likes of Colin Slade and Aaron Cruden ... one man's misery is another man's joy."
The All Black players had a day off yesterday, with some going golfing and others just relaxing at their North Shore base.
