Captain Michael Ballack was one of five players forced out of the squad through injury and the team's two chief strikers netted only a handful of goals between them in the German league last season.
While Spain and Brazil have yet to play, Germany's performance was the most impressive so far at the World Cup and it will focus minds in Group C as the team that comes second will face the winners of Germany's Group D in the second round.
British bookmakers cut the odds on Germany winning their fourth World Cup to 9-1 from 12-1 immediately after the match.
The Australian defence had been expected to mount stiff resistance to the out-of-form strikers Miroslav Klose and Lukas Podolski.
But unlike France against Uruguay, the German side unlocked the Australian defence with neat passing down the flanks and penetration through the middle from the 21-year-old pivot of the team, Mesut Ozil.
Captain Philipp Lahm linked deftly with Ozil and the 20-year-old right winger Thomas Muller to leave the Australians floundering, carving out a string of openings in the first 20 minutes that should have produced more goals.
Coach Joachim Low said afterwards that Muller had been chosen over the more experienced Piotr Trochowski precisely for his ability to carry the ball to the edge of the penalty box and really penetrate dogged defences.
Low will also be pleased that in-form striker Cacau came off the bench and buried his first chance to round off the German win, despite being left out for Klose.
"It was a difficult decision not to field Cacau straightaway," said Low after the game. "I just knew I had a strong substitute there on the bench."
Low said it had been important for the team to get a sound win under their belts to build confidence and that the defence had been excellent. He warned it was just the start, but his youthful side has already proved many doubters wrong.
England will now be all the more anxious to avoid coming second in Group C and running the risk of facing Germany in the second round.
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