Grella has played on some of the world's best players and knows how hard it can be to stop a talisman like Schweinsteiger from having an influence on the game.

Australia's midfield enforcer respects the Bayern Munich man enormously and thinks that he can be the player to fill the shoes of injured German captain Michael Ballack.

"What a great player, what more to say. He's been playing at the top level for a long time now. He's moved positions, he started as more of a winger. Now he has moved into the middle of midfield," Grella said.

"He's very dangerous with the ball at his feet. I think he can pick a pass. He has a great shot, we are going to have to be careful and not let him shoot from outside the box.

"I think he'll get their play started, I think he can find a pass. If I'm selected, I'm going to have to be very aware of closing his space and time down."

Ballack's loss was a huge one from Joachim Low's team, with the experienced captain injured in a crude tackle while playing for Chelsea in the FA Cup final just a month before the tournament.

But Grella thinks that Ballack's absence could provide Schweinsteiger with the opportunity to step up and become Germany's main man.

"I think he can (fill Ballack's shoes). They are different players, but I think he's maybe more dangerous at delivery in and around the box and we are going to have to pay a lot of attention to that," he said.

Grella respects Germany's depth enormously and knows it is more than just a one-man side. The one player which he doesn't know a lot about, but could end up playing a major role on Sunday is young dynamo Mesut Ozil and Grella has been watching him closely.

"I've seen him a little bit in the game against Hungary. I watched the first half. He moved well. He does what Tim Cahill does, which is play behind the backs of the two midfielders, which can cause problems," he added.

"What we've been working on at training, about being compact. If we are compact then it will be hard for him to find spaces."