Ange Postecoglou believes he could pick a handful of different winning line-ups for Thursday night's clash against Saudi Arabia - but is refusing to give any clues to his preferred XI.

Australia takes on the Green Falcons at Adelaide Oval in a must-win clash for the side’s hopes of automatic qualification, with Postecoglou confirming all 23 squad members except the suspended Mark Milligan are available for selection.

PIC SPECIAL: Socceroos training in Adelaide

Adelaide-born defender Ryan McGowan arrived in camp on Tuesday night after flight delays from China and Postecoglou said his chances of playing were “very small” given his preparation.

However, the Australia coach wouldn’t be drawn on his likely starting team and claimed before Wednesday night’s final training session that he still had not decided it himself.

“They’ve given me a tough one. I’ll sleep on it tonight,” Postecoglou said. “I reckon I could come up with three or four different formations and still look like a genius.

“I’m in a decent spot. We’ve got training today. I’m always mindful to get that final training session done and dusted.

“Sometimes I’ll wait until the next morning until they’ve all woken up and been cleared by the medical crew. I always have some flexibility in my mind.”

Postecoglou has a plethora of midfield options to weigh up with Tom Rogic and Aaron Mooy both in brilliant form and both having missed the last qualifier against UAE.

Jackson Irvine was outstanding in their absence, while Massimo Luongo is also available again after missing the UAE game through injury.

The Australia boss also has a headache in defence, with the centre-back Matt Spiranovic (quad) injured, while his usual partner Trent Sainsbury is short on game-time.