Chelsea midfielder Michael Ballack believes Australia will be a tough opponent in the group stage of the 2010 World Cup.

The Germany captain admitted that the national team's recent form was not as good as the critics have said and concedes it will be a fierce battle to even get past the group stage against opponents Australia, Serbia and Ghana.

"We do not have the consistency or strength in depth in the squad," Ballack told German magazine Kicker.

"We have been too weak, particularly in friendlies, to be able to say we have the class to beat everybody else.

"You can forget about us having had the luck of the draw - we have a tough group and all three opponents are uncomfortable and physically very strong.

"We are going to have to put our foot down from the very beginning."

Germany takes on Australia in their opening group match on June 13, 2010 in Durban, South Africa.

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