Australia aiming to attack high-flying Dutch in Group B
Australia's Mathew Leckie controls the ball during their World Cup Group B match against Chile at the Pantanal Arena in Cuiaba, Brazil on June 13, 2014 - by Martin Bernetti
The Socceroos desperately need to take something from the game if they are to match their run to the last 16 from 2006 after going down 3-1 to Chile in their opening match.
And Postecoglou thinks attack will be the best form of defence for his side as they bear up to the challenge of facing the in-form Robin Van Persie and Arjen Robben, who both struck twice against Spain.
"We know we have to be strong defensively, the Dutch are dangerous going forward as they showed against Spain," he told media ahead of Wednesday's game.
"We know that Van Persie and Robben will be a challenge, but we knew that coming into the tournament.
"In saying that we also need to be attack-minded, we can't just defend for 90 minutes."
After being drawn in one of the toughest groups in the competition alongside the Netherlands, Chile and Spain, many believed the Socceroos should start building towards the 2015 Asian Cup on home soil.
However, Postecoglou doesn't want the experience of playing on the biggest stage in world football to pass his young squad by.
"We just have to believe in what we do and tomorrow we will get a chance to find out where we are at," he said.
"There’s a lot at stake for both teams. For us if we don’t get a result it’s the end of our tournament."
The Netherlands will be full of confidence heading into the clash in Porto Alegre, but coach Louis van Gaal has told his players to keep their feet on the ground after the euphoria of avenging their defeat to Spain in the 2010 final in such style.
"You win the World Cup by winning the final," said the newly appointed Manchester United manager.
"This is just the first step. We have to keep our feet on the ground, we shouldn't get ahead of ourselves. We need to prove our capability to win over Australia, which would be that easy."
In recent tournaments the likes the Robben, Van Persie and Wesley Sneijder have been part of Dutch sides that have started a tournament brilliantly, only to fizzle out in the latter stages.
And Van Gaal believes having their experience on board makes his job a lot easier.
"I felt the team reacted very well, especially the older players. The more seasoned players know what is going on and they immediately warned the team this was simply one victory and that we haven't earned anything," he added.
"We haven't even made it to the next round yet so anything can happen and I'm very glad to see this. That means a coach doesn't have to say much more,"
Dutch concerns over the fitness of centre back Ron Vlaar were eased by Van Gaal on Tuesday as he insisted he has a fully-fit squad to choose from.
However, Postecoglou will be forced into at least one change due to an injury suffered by Ivan Franjic, with former Heart of Midlothian defender Ryan McGowan set to deputise.