The Australians have been talking down their chances of beating Brazil in Sunday's Group F match in Munich but are still quietly confident of pulling off an upset following their euphoric 3-1 win over Japan in Kaiserslautern on Monday.

"Obviously there is a little bit of respect because they are world champions, but you just go out there and you play to what you're capable of playing," Australia striker Harry Kewell told reporters before training.

"You're not going to go into a game thinking you're going to lose. You're going to go in thinking you're going to win it, and that's how we are going to start."

Socceroos captain Mark Viduka said his team had detected some weaknesses in Brazil's game during their laboured 1-0 win over Croatia on Tuesday.

"Everybody wants to do well against Brazil but the game against Croatia showed that they are vulnerable in close," Viduka said.

"I thought Croatia should have got something out of that game because they were the better team."

Defender Lucas Neill said there was a chance the Australians could sneak under Brazil's guard because the South Americans might possibly underestimate them.

"We're technically not as gifted as them but maybe we are a little bit more hungry," he said.

"They've been there and done that so many times and we've got more to prove than them so it's like David and Goliath I suppose."

Hiddink, a shrewd tactician who took the Netherlands and South Korea to the semi-finals at the previous two World Cups, has kept everyone, including his own players, guessing about his plans for the match.

The crafty Dutchman hinted that he might field a weakened team to save his best players for the final group match against Croatia but no one really knows what he has in store for the world champions.

"Even I haven't got a clue," Viduka told reporters before Friday's closed practice session at Oehringen. "But we're going to work on some tactical things today."