"We have to win your home games as it will be tough to pick up points on the road," said Postecoglou.
"With a scrappy victory, you get three points but it doesn't show the road ahead is going to be where you want it to be.
"I still want us to perform strongly. I want to win but also play well so we have confidence in what we're doing."
At Postecoglou's disposal are 23 fit players, including 21 who ply their trade abroad.
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"If somebody can try to tell me what my strongest 11 is then good luck to them but it'd be a guess," Postecoglou added.
"I have four or five starting 11s I could put out tomorrow and I'd feel confident about all of them getting the job done."
Iraq's squad features a number of players from their Rio Olympics campaign where the team were eliminated in the group stage after three draws, including one against hosts and gold-medalists Brazil.
Postecoglou said his team, who will next meet United Arab Emirates on Tuesday night in Abu Dhabi, have done their home work on Iraq.
"We've been following Iraq since the draw. We know everything we need to know about them," the manager said.
Japan, Saudi Arabia, United Arab Emirates and Thailand are the other teams in group B.
(Reporting by Sudipto Ganguly in Mumbai; editing by Amlan Chakraborty)
