Australia forward Tim Cahill promised his team would learn from Friday's 3-1 loss to Chile in their World Cup opener and insisted the Socceroos remained full of belief for the rest of their Group B campaign.

The South Americans had threatened a rout after goals from Alexis Sanchez and Jorge Valdivia in a whirlwind opening 15 minutes at the Arena Pantanal in Cuiaba.

But pool outsiders Australia, who face further group matches against Holland and Spain, showed fighting spirit to reply through Cahill and went close to equalising before Jean Beausejour secured the points in stoppage time.

"It is all about defining moments," Cahill said after the game. "This is a stage to do it. When you are called upon, you have to show up.

"At the start, we showed a bit of fear, and then when we stepped up and started getting in their faces and rolling them a little bit. When they showed a bit of aggression, we have to show it back. We did that.

"We will learn from this and we will go into the next game [against Holland on Wednesday] very positive. We believe in our football, we believe in our structure.

"Last week they were questioning whether we could create chances. Tonight we created quite a lot."

Early in the second half the former Everton player headed past Claudio Bravo for a second time, only to be frustrated by an offside flag.

"I don't know if it was a disallowed goal or not, but not a lot went our way tonight," he said.

Cahill, now with New York Red Bulls, added: "They got in twice and punished us, but really after that you could see their legs were going.

"We knew we could get something from this game and, when you concede like that at the end, it is disappointing.

"But, overall, for a team performance, we really stood up strong and it is just unfortunate."