Germany coach Jurgen Klinsmann says that skipper Michael Ballack will be the crucial figure in his side's bid to beat Argentina in the World Cup quarter-finals.

Chelsea new boy Ballack was the star of the German side that reached the final four years ago, but Klinsmann believes that his influence is even greater now.

He said: "Ballack over the last two years has helped tremendously to make this team grow.

"He is a leader on the field with what he does playing-wise. But also behind the scenes he is of tremendous importance. He is talking to the younger players and points out mistakes.

"He is critical with his team-mates and also with us sometimes and that is important, too. We have a lot of discussions.

"He has made a major step in his development in the last two years and there is still a lot more to come from Michael."