Talismanic striker Alexandra Popp scored twice as Germany thumped debutants Morocco 6-0 to launch their Women's World Cup title charge in ominous fashion on Monday.

Popp's 12th-minute header set the Germans on their way in Melbourne as Morocco's piece of history -- the first Arab team at a Women's World Cup -- started badly and ultimately ended in humiliation.

The German skipper Popp collected another goal before the break, Klara Buehl added a third in their first attack after the restart, before own goals from Hanane Ait El Haj and Zineb Redouani.

A last-minute strike from substitute Lea Schueller completed the rout as the two-times former champions romped to the biggest win of the tournament so far.

On paper it was the biggest mismatch of the group stage, with 70 places separating them in the world rankings, and the gulf was apparent from the off.

The Atlas Lionesses showed glimpses of magic and had a goal disallowed.

However, a fairytale win never looked likely in front of 27,256 fans at Melbourne Rectangular Stadium, a near full-house.

"We're super-happy we were able to play like this in our opening match. It's always difficult because you don't really know where you stand or how your opponent will play," said skipper Popp.

"But we were able to impose our game. To have this kind of atmosphere in a stadium like this, that's what a World Cup is all about. It pushes you, the fans carry you."

Germany, who won the World Cup in 2003 and 2007, went out in the quarter-finals four years ago.

But since then coach Martina Voss-Tecklenburg has overseen impressive progress, shaping a dynamic, front-foot team which finished runners-up at last year's Euros to England.

"Today we came up against a team that was superior. It was David and Goliath," said Morocco's French coach Reynald Pedros.

"They had something we didn't. But we will stay positive and keep our heads up."

Germany had their first look at goal when Buehl's low freekick fizzed wide.

They kept pressing and opened their account when Wolfsburg's Popp climbed unmarked to head in her 63rd international goal from a pinpoint Kathrin Hendrich cross.

Morocco were on the back foot but skipper Ghizlane Chebbak had a sniff of goal midway through the half, only for her long-range strike to be comfortably collected.

Lyon's Sara Daebritz found the back of the net with a tidy finish soon after as Germany probed for an inevitable second, but the goal was ruled offside.

The second came seven minutes before the break with Popp, facing away from goal, shouldering home after Buehl's menacing corner.

Buehl then pounced for a third seconds after the restart with Morocco still asleep, rifling home the rebound after Lina Magull hit the woodwork.

In end-to-end action, Anissa Lahmari was denied a historic first World Cup goal for Morocco when she was adjudged offside, before play switched back to the other half and Ait El Haj's own goal.

The defender turned the ball into her own net after a defensive header ricocheted off her shin, with the second own goal coming as Redouani desperately tried to clear off the line.

Schueller made it six from close in as the clock ticked down, with a seventh denied by the offside flag.

Colombia and South Korea are also in their group and play on Tuesday.