Argentina's Rodrigo De Paul says the national team are wary of Australia's height and speed ahead of their World Cup last-16 clash in Doha on Saturday.
The midfielder pointed to the Socceroos' flying wingers Craig Goodwin and Mathew Leckie as the danger men.
"They are a very fast team that places a lot of emphasis on the flank players," said De Paul, who has played every minute for Argentina in Qatar. "Tall guys, tall centre-backs, we'll have to avoid giving away free-kicks around the box. We'll have to be careful [of their] very fast wingers, that's their strength, counter-attacking."
Australia got off to a poor start at the World Cup despite taking an early lead against France, eventually succumbing 4-1. But 1-0 victories over Tunisia and Denmark booked the world's 38th-ranked side a surprise ticket to the knockout phase.
However, coach Lionel Scaloni said it was not a shock to see the Socceroos progress in Qatar.
"It didn't surprise me because they are a good team... with a World Cup history, which makes them difficult," he told a pre-match press conference on Friday. "Whether or not they are inferior to us remains to be seen. I don't agree that they are. This is football -- eleven against eleven. Forget who is theoretically favourites and let's play football."
Scaloni is expecting the Ahmad Bin Ali Stadium to be teeming with Argentina fans on Saturday, as the Stadium 974 was for Wednesday's victory over Poland.
"The Argentine fans always make themselves heard and when the stadium is 80 to 90 percent Argentines you notice it more," he said. "Hopefully tomorrow it will be like the Poland match because that was like playing in Argentina."
Images have been shared from across the world of Argentina fans cheering on the team, even from as far away as Bangladesh.
"For many years now, with Diego [Maradona] with Leo [Lionel Messi] the shirt has always generated hysteria, for the colours, for the Argentine passion," said Scaloni. "It fills us with pride that a country like Bangladesh supports Argentina."