Socceroos in huge selection shake-up

Ange Postecoglou has pulled a major Socceroos selection shock, rolling out a new-look, aggressive formation for Thursday night's (AEDT) crunch World Cup qualifier against Iraq.

Australia will play with a back three anchored by Mark Milligan at the PAS Stadium in Tehran.

Milos Degenek and Bailey Wright are the other defenders while captain Mile Jedinak, Massimo Luongo, Aaron Mooy and Jackson Irvine - the latter handed his first start at international level - comprise a four-man midfield.

There are no fullbacks, with Robbie Kruse and Mathew Leckie deployed out wide and Tomi Juric the lone man up front.

In another shock move, Mitch Langerak has been preferred as goalkeeper instead of Mat Ryan

Postecoglou believes the new system will not only take the Socceroos to next year's World Cup but ensure they are as competitive as possible once they are there.

Australia are third in Group B while Iraq, who are fifth, effectively need to win the match to keep their qualification hopes alive.

Socceroos: Mitch Langerak, Milos Degenek, Bailey Wright, Mark Milligan, Mile Jedinak (capt), Jackson Irvine, Aaron Mooy, Massimo Luongo, Robbie Kruse, Mathew Leckie, Tomi Juric.