New Zealand have talked up Argentina ahead of their World Cup sudden-death clash on Sunday, rating it their toughest game of the tournament so far after a discreet first-hand look at them in action. All Blacks assistant coach Wayne Smith revealed Tuesday he attended the Argentina game against Scotland in Wellington, where he said the view gave a far better impression of developments than video replays. "They're going to be a physical test and they're also going to be a tactical test because they are pretty smart," Smith said, likening playing Argentina to matches against England and South Africa. "They're tough physically, they take a lot of pride from their pack and the way it performs and scrum and lineout and breakdown," the former All Blacks fly-half added. "They've got a very good defensive system. I went along and watched them play Scotland when we were in Wellington and I was really impressed with their system. "They don't over commit there, they always have players on their feet available." Argentina qualified for the quarter-finals after bouncing back from a narrow loss to England in their opening game to upset Scotland and complete regulation victories over Georgia and Romania. In their four pool matches they only conceded in three tries, a record only bettered by England (one) and South Africa (two) while the All Blacks leaked six tries but were the top-try scoring team with 36. The All Blacks are the top seeds of the final eight with Argentina at the bottom but "it's going to be a massive test," said New Zealand wing Richard Kahui. "It's certainly a completely different ball game from those pool matches and you live or die on Sunday night so it will be a huge test." Argentina have never beaten the All Blacks in 13 Tests, with their best result a 21-21 draw in Buenos Aires back in 1985. But New Zealand No 8 Kieran Read rated Argentina as the toughest match of the tournament so far for the All Blacks who disposed of France, their only serious competition in pool play, 37-17. "The Pumas are a dangerous side," Read said. "Their strength is in their forwards and I think that there's no hiding behind that. "They're going to really attack us in that area and I think they'll really look to try and gain territory and kick really well and try and keep the scoreboard ticking over against us. "That's where we've got to be really strong and not give away too many penalties, be disciplined and really try and attack them at their strength."