To see the Socceroos train overnight...

Grella, who has had a cold this week, believes the Australian players are close to their physical peak, with only Tim Cahill sitting out Tuesday's training session at St Stithians College in suburban Johannesburg.

While the gruelling physical preparation the Socceroos have undertaken since arriving in South Africa was one reason for the 3-1 loss to the USA, Grella said psychologically, it made the whole team aware of the level of commitment needed to progress from a difficult Group D.

"I think we've put in a lot of hard work," he said. "We had a small little slap in the face against the USA. We've started going through the bits and pieces of the game.

"I think there's some smaller detail to ensure we are super conditioned. On the physical side of things, we've ticked that box.

"We were given the information before the Denmark game that we were going to be putting in a certain amount of work and while the two friendly games are important because everyone is watching us, we knew that the legs weren't going to turn over as much as we wanted to.

"Maybe some things wouldn't come as easy as we would want them, but we've got that out of the way now. We can concentrate on sharpening up. I think the players are confident that we can perform."

Grella is well aware that Australia's preparation is more than just physical and he said the last few days before the tournament starts will be used to fine tune the team's skills.

"Tactically we can always improve," he said. "I don't think because you've played football for 10 years that it means you're a perfect footballer.

"You can always get better, you can always improve and sometimes when you have an average game like that, it can be good reminder that you have to keep your antennas up."

With physical and tactical preparations firmly on track, Grella believes the psychological build-up will hold no concerns for a determined Australian team ahead of the match against Germany.

"It's a reflection on our team, we have some boys that have got steel and we've got some boys that have got class and I think if make them hit together on the right spot on the pitch, we will put the Germans under a lot of pressure," he said.

But he expects the Germans to be ready for whatever the Socceroos throw at them as well.

He added: "We've done really well and if you look at our World Cup qualification, there's not many teams which qualified with those type of points.

"I think they'll give us the respect we deserve."

To see the Socceroos train overnight...