Germany began their quest for a fourth World Cup in devastating style Sunday with a thumping 4-0 victory over Australia in their opening Group D match.

With a fluent performance fitting for the first match of the tournament at the magnificent Moses Mabhida stadium, the youngest German World Cup squad for three quarters of a century put down their marker as serious title contenders.

Forwards Lukas Podolski and Miroslav Klose gave their side a 2-0 halftime lead to vindicate coach Joachim Loew's faith in them despite a recent lack of goals, with winger Thomas Mueller and substitute Cacau finding the net after the break.

Australia, who started both halves brightly and battled gamely throughout, played the last 34 minutes with 10 men after Tim Cahill was dismissed for clattering into Bastian Schweinsteiger.

Germany lead Group D from Ghana, who beat Serbia 1-0 in Sunday's earlier match in Pretoria.

"It was very important that we won because we gained a lot of self confidence," said Loew, whose team face the Serbians next on June 18.

"We can now hope to make the last 16 with just one more win. All players were very, very focussed. We did many things right but this is just the start," he added.

It was the triumvirate of captain Philipp Lahm, Mesut Ozil and Mueller who laid the foundation for victory as the Germans took to the wings and fired in low, hard passes to outflank and unpick the much-vaunted Socceroo defence.

"I think the way we set up our attacks, the way we passed balls to and fro is something we have been working on very intensively over the past few years," Loew said.

"We were very good on the ball and we created beautiful goals," he added.

In the eighth minute, Ozil found Mueller in what looked to be an offside position and his cutback allowed Podolski to smash the ball into the net via Mark Schwarzer's flailing arm.

Klose should have doubled the lead in the 24th minute but he blasted wide when Podolski's cross left him free in front of goal. He made amends just two minutes later, however.

Lahm lofted a high cross in from the right, Schwarzer came charging out to claim the ball but Klose beat him to it and headed into an empty net for his 49th international goal.

"Everything worked today," said the 32-year-old, top scorer at the last World Cup on home soil.

"We have three points in the bag but we have not won anything yet. But we did gain a lot of respect with this success tonight," he added.

With the Australian spirit sapped in the second half by Cahill's sending off, Mueller got his reward for a fine performance on the right flank when he found space in the box and screwed the ball into the net off the post in the 68th minute.

Cacau, who had just replaced Klose, completed the scoring two minutes later after Ozil had beaten the offside trap to play in the striker to drill the ball into the net.

"It was not the day for us," said Australia coach Pim Verbeek. "They were better and the reality is the next two games we have to win. There is no discussion about that. Drawing is not enough.

"We have six days to recover physically and mentally and then we have to show the right spirit," he added.

Verbeek said Germany had shown they were a "fantastic side" and had not been weakened by playing youngsters.

"Every player they brought in made the team not weaker but stronger," the Dutchman added.