He’s had a month to shape, mould and motivate and now the World Cup is here and all that Socceroos coach Ange Postecoglou has put in place is about to face the ultimate test.

At the end of four weeks of intense preparation that started in Gosford and climaxed in Vitoria all 23 squad members have been declared fit and available for their crucial opening match against Chile in Cuiaba on Friday (Saturday AEST).

But physical fitness aside, Postecoglou knows the biggest challenge for his relatively young and inexperienced side ranked the lowest in this World Cup, will be a mental one.

“Our belief in what we do will get tested at some point during the game,” he said.

“There are quality individuals and quality teams who will try to break us. If we get through that battle and grow as the game goes on, the confidence will grow.

“For a lot of these players it’s their first go at the big stage and I’m sure there’s a little bit of uncertainty in their heads. If we can get through those initial moments we’ll be fine.”

On the field though it will be the defence of keeper Mat Ryan centrebacks Matthew Spiranovic and Alex Wilkinson and fullbacks Ivan Franjic and Jason Davidson who will come under the most fire.

Chile’s Barcelona striker Alexis Sanchez headlines a fiercely attacking side who’s high intensity style has the capacity to run rings around the Socceroos.

But Postecoglou feels their biggest weapon – and what has made them the tournament’s dark horses – is belief.

“Chile’s aspirations are not just to get out of the group but really do something in the tournament,” he said.

“It’s a World Cup, the pressures are unique. The best teams can crumble and the most unlikely teams can rise.

“Chile have a great belief. Any team you face at any level who have a great deal of belief in themselves are a difficult opponent.

“You know that no matter how the game goes, they’re going to stick to their way of football. That gives them tremendous confidence going into every game, and that’s our challenge.”

Only six of Australia’s 23-man squad have experienced a World Cup before.

But it’s also Postecoglou’s debut on the biggest stage of all having never been to the tournament, not even as a spectator.

But while he admits his players may be feeling the nerves, he says won’t be .

“It’s a World Cup, a special occasion. But I’m not as green as people make me out to be,” he said.

“I’m loving the fact we’re going to test ourselves against the best and the environment we’ve created for the players. They’re responding.

“I’m feeling good about how we’ve prepared.

“I’ve worked hard for this. I feel privileged to be in charge on a temporary basis and you want to appreciate the big moments.

“I’ll take a moment to take it all in, then it’s my job to help the players take their opportunity.”

As for his final message to his troops before sending them into battle.

“I might crack a couple of gags, I’m a funny guy,” he said.

“We’ve said all along let’s test ourselves, and I think we’re ready for that.”