Germany [Images] coach Juergen Klinsmann said he could not risk playing captain Michael Ballack [Images] in the World Cup opener against Costa Rica on Friday.

"I had to tell him: 'Michael, there's a risk. You haven't trained for a week," Klinsmann told German public television after leaving Ballack on the sidelines for the 4-2 win.

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"At the end of the day it's the coach's responsibility," he added after Ballack, who has struggled all week with a calf injury, declared himself fit on the eve of the match.

Asked if he was upset with Ballack, Germany's most creative midfield force, Klinsmann said: "No, not at all.

"Everyone wants to play. Every player says they want to play.

"I talked to him this morning and said: 'I know you want to play', but I told him it's my responsibility.

"We're waiting for Michael. Now he'll train very hard and he'll be fit for the Poland match (on Wednesday)."

Klinsmann replaced Ballack in central midfield with Tim Borowski, who played well until he was taken off after 72 minutes.

The coach said: "We know his abilities. Tim was constantly moving and he worked really hard on defence.

"He makes it tough for us to pick a team. He wants to get into the starting lineup in the Torsten Frings (midfield) position."

Frings scored a fantastic fourth goal for Germany with a curling 30-metre drive to cap a fine performance.

He was handed the captain's armband when Bernd Schneider was substituted in injury time.

Klinsmann was happy with the display but already looking towards their next group match.

"At such a mega event like a World Cup we've got to put this (game) behind us quickly. They can have a little glass of beer tonight if they want but our focus has to turn right away to the next match no matter what happens," he said.

"This was a lot of fun."

(Additional reporting by Erik Kirschbaum)