DUISBURG, Germany (Reuters) -- Italy goalkeeper Gianluigi Buffon said second round opponents Australia represent a tough test for the Azzurri and that Marcello Lippi's side will not underestimate them.

"It will be a tough one, even if objectively they have to be considered manageable opponents," the Italy keeper told reporters after training on Friday.

"They are very strong physically and are an enterprising side who have a lot of confidence in themselves. They have scored five goals in their three games and we need to be very careful because they have nothing to lose against us," said Buffon.

Italy, whose win over the Czech Republic on Monday booked their place in the last 16, struggled to a 1-1 draw in their second group game against the United States and Buffon said that match should serve as a warning.

"We won't make the mistake we made against the U.S. again. In this game there will be no second chance -- it's win or go home. It will be vital to be at our top physically and mentally," he said.

"They are a similar side to the Americans but against the U.S. we made problems for ourselves and we won't do that again," added Buffon.

Australia coach Guus Hiddink is well known to the Azzurri as he eliminated them from the World Cup at the same stage four years ago when he was in charge of co-hosts South Korea and Buffon said he had the utmost respect for the Dutchman.

"He is a great coach and his results speak for themselves -- he has achieved historic results with teams that have not been exceptional. But lots of things have changed on our side in the last four years," said the keeper.

Italy defender Marco Materazzi, in line to start against the Aussies if Alessandro Nesta doesn't recover from a muscle injury, said the team would not be fazed by coming up against Hiddink and his team.

"We know that he is a great coach and that he is in charge of a physical and good team. But we are Italy and we were prepared for the eventuality that we might have to face Brazil," said Materazzi.