Australia coach Ange Postecoglou said the 35-year-old striker would lead the side in Tuesday’s Group A clash with Oman after regular skipper Mile Jedinak was ruled out with an ankle injury.
Cahill captained Australia once before at the 2010 World Cup in South Africa and said it was an honour to be given the job a second time.
“I don’t really want to put too much emphasis on it because Mile is our captain,” said Cahill.
“It’s a massive honour and something that is great in my career to have, but it’s a great responsibility that I will make sure I deliver in the right way.”
Australia won their opening match 4-1 against Kuwait in Melbourne and know a victory over Oman in Sydney would likely secure their place in the quarter-finals.
But Postecoglou said it was also important that the players remain fresh for the campaign so he planned to ring in several changes.
“We’ve learnt pretty clearly at the World Cup, by the third game against Spain we were pretty spent as a group because we relied on a core group of players,” Postecoglou said.
“We don’t want to fall into the same trap. We want to do well in all three games and tomorrow night is a very, very important game for us.”
Australia are overwhelming favourites to beat Oman, who lost their opening match 1-0 to South Korea, but Cahill said the Socceroos were expecting a tough encounter.
“We know that they’ve got a great squad and a coach that has been with them for a very long time,” Cahill said.
“So the familiarity for their team and of their players playing together, they’ve got the upper hand there.
“When it comes to us, we just have to focus on ourselves. We’ve trained well, we’ve had a great start. We know this is going to be a difficult opposition.”
(Reporting by Julian Linden in Brisbane. Editing by Patrick Johnston)