The Socceroos can take a huge step towards the Asian Cup second stage by beating Iraq after Thailand stunned Oman in a massive Group A shock on Thursday night.

The co-hosts beat Oman 2-0 - the Gulf state looking little like the side which troubled Australia so deeply in a 1-1 draw last Sunday.

With Thailand now clear atop their group, Australia must now beat Iraq at Rajamangala Stadium on Friday night to keep pace and then chase a win against the Thais on Monday to ensure they finish on top of Group A.

Only the top two teams in the group qualify for the quarter-finals - the group winner remaining in Bangkok with second place facing a quarter-final in Hanoi, Vietnam.

Thai pin-up boy Teerathep Winothai set up two second half goals for fellow substitute Pipat Thonkanya to ensure the victory in front of another disappointing crowd of around 20,000 at the 60,000 capacity Rajamangala Stadium.

Socceroos coach Graham Arnold said he expected a marked improvement against Iraq as his side built on their Asian Cup opener.

"What people don't understand is that the Oman game was the players' second game in six weeks," Arnold said.

"I knew they were going to be underdone ... I expect a much better performance (against Iraq)."

Arnold has earmarked keeping possession as the major area the team needed to improve, both to ensure they had the means to play football and conserve as much energy as possible by not having to pursue opponents.

"We turned over possession 50 times in 90 minutes. Statistics show that when we regained possession we gave the ball away 29 times on the first or second pass," Arnold said.

"That shows we had to do a lot of chasing to get the ball back which costs a lot of energy."

Defender Lucas Neill said the team had been unhappy with how they performed against Oman and wanted to put things right.

"I expect a reaction. In tomorrow's game I expect us to make a different kind of statement," Neill said.

"I would say the players are a little bit disappointed by their personal performance and the team performance."

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