The tournament favourites needed an injury-time strike from the Everton star to salvage a 1-1 draw in driving rain to stay alive in their first continental campaign.

Cahill conjured memories of his late intervention to help Australia beat Japan at last year's World Cup with his volley from close range to bring relief to the Australian camp after a frustrating 90 minutes.

Coach Graham Arnold admitted his star-studded side were lucky.

"I'm relieved and distressed. We just got out of jail," he said.

"It shows how difficult Asia is. It shows that we need to push ourselves to the limit."

He said his team were exhausted by the heat and humidity, but praised them for never giving up.

"Some players lost four or five kilos out there, but they gave it everything. The players are dead," he said.

"But I'm still confident everything will be fine."

With Thailand and Iraq also drawing 1-1 in their opening game on Saturday, the group remains wide open.

The Gulf state, ranked 74 and playing against the Australians for the first time, frustrated their 48th-ranked opponents and stoically protected a 32nd-minute lead with a packed defence and questionable injury-feigning tactics.

Up to Cahill's strike it looked grim for the Australians.

Playing in the Bangkok heat and in front of a meagre crowd in the 60,000-capacity Rajamangala Stadium, the Aussies, who reached the second round of last year's World Cup, threw everything at Oman in the second half before Cahill's last gasp equaliser.

The Omanis rocked the Socceroos with a shock lead through Badar Mubarak and the task became harder for Australia as a tropical downpour drenched the stadium in the closing 15 minutes.

Oman struck their telling blow when Mubarak finished off great work on the left by Imad Ali who found Mubarak in space with the Socceroo defence pulled out of shape.

Mubarak smashed home past Schwarzer's right hand and the Oman team celebrated by grouping in front of a contingent of Australian fans and orchestrating Muslim prayers to boos.

Oman's tactics became obvious after the goal with players going to ground for treatment after contesting the ball and forcing referee Eddy Maillet to constantly stop the game to seek treatment.

"Of course I am disappointed because I thought Oman was the best team and we should have won," said their Argentine coach Gabriel Calderon.

"It was a very technical match, Australia are very tough."

He likened the match to a cup final, and said their remaining two games in the group would be treated in the same way.

"For Oman, we are playing three finals. Today was number one and Thailand and Iraq will be two and three," he said.

While the Australians brought on second-half substitutes John Aloisi, Cahill and Brett Holman in a bid to turn the match around, they needed two great saves from Schwarzer to keep them in the match.

Liverpool star Harry Kewell laboured in the humid conditions with his touch letting him down while skipper Mark Viduka was rarely a scoring threat.