Socceroo boss Ange Postecoglou is set to field what amounts to his strongest available team when he seeks to get another marker on his team's competitiveness in the friendly match against World Cup dark horses Croatia in Salvador on Friday night (Saturday morning AEST).

The only ''big'' player set to miss is midfielder Mark Bresciano, who is still plagued by a back problem. It must be causing increasing concern in the management ranks with the opening game against Chile scheduled for a week later than the Croatia fixture.

The coach played a practice game at training on Wednesday which suggested he had settled on Alex Wilkinson as the central defensive partner for Matthew Spiranovic, seemingly preferring the South Korean-based former Central Coast Mariner to rivals Bailey Wright and Ryan McGowan.

Interestingly, with Bresciano under an injury cloud, Postecoglou experimented with Tommy Oar, often deployed as a winger, in the ''number ten'' role behind frontman Tim Cahill. The move has been widely interpreted as a test to see whether Oar could provide an option in that position to James Troisi for the World Cup opener if Bresciano is unavailable, which has to be a possibility.

If Oar starts there it will allow Posteocglou to use the speedy Ben Halloran on one flank and the muscular and quick Matthew Leckie on the other, giving the Socceroos the chance to break at pace in transition.

Croatia has a slew of top class players headed by Champions League winner Luka Modric, once of Tottenham but now of Real Madrid. It stumbled in its qualifying programme and made it through the playoffs but it has the class and quality to trouble any opponent, including in its opening night fixture against host Brazil.

It also has a short but deeply entrenched football rivalry with Australia. Socceroo veteran Tim Cahill remembers well the emotional game in which Australia came from behind to draw 2-2 with the Balkan team in the 2006 World Cup in Germany.

The result allowed Australia to qualify for the knock out phase at their rivals' expense.

''Going through that game was one of the biggest, proudest moments for Australian football. They had a very well stocked team, we had as well and it showed how much spirit and fight the Australians had and how much respect we earned that night.

''I am pretty sure that regardless of the players we had back then they didn't expect us to go that far and to get that result. We are looking forward to playing against these players (on Friday night), it will be a good test for where we are going because they have got a really difficult group and they will be wanting to make an impact for themselves.

''Our focus is a good performance against Croatia, a high intensity game would be a good test, and at the same time not giving too much away. Against Chile, we know the way they play, we are watching videos and they are in the unknown with us, and that's the way I want to keep it.''

Modric is the stand-out in the Croatian line up but Cahill backs Australia's captain to handle him.

''He's an exceptional player. I played against him numerous amount of times. People think he can't take it physically, but playing in the Premier League shows he can. I think Mile (Jedinak) will be able to deal with him well if he plays, and the boys in the middle.

''The more we get in their faces and upset their rhythm....we don't want to make it easy for anyone. We want them to come off the park and say I don't want to play that Australian team again. But at the same time we want to play good football.

"All the players they have in their team play in world class teams, but for us its not about names, its about what we can do, maybe leaving a little thought in their mind about a few of the players we have."