Injured German captain Michael Ballack has warned his teammates of the dangers they face in Group D of next month's World Cup. The Chelsea midfielder, who will miss the entire tournament because of an ankle injury, knows Die Mannschaft will have to be on top of their game to get through the group stage as they face tough opponents in Australia, Serbia and Ghana.

"Straight after the draw was made, I said that people should know that you can lose against anybody in the group stages. Australia, Serbia and Ghana are all athletic, robust teams," he told Stern magazine.

"Our team will have to push itself to the limit to beat big nations in the knock-out phase, and that was also the case before my withdrawal - and that is still the case."

Ballack also said that Germany are expected to win and progress through the stages which can be very daunting for some players, especially the younger ones.

"Germany is a nation which must always win," he said.

"You really have to suffer to get to the point where the real suffering begins. You are only respected when you win.

"This is brutal for sportspeople, particularly for youngsters. That will be the case for our lads in South Africa.

"It's awful for the team when they can only really enjoy the tournament from the semi-finals.

"Anything else would mean failure. To start with, the aim is purely to avoid a catastrophe. That does push you and motivate you, but it is a merciless game."