The Socceroos' chances of getting out of their group are in immediate strife after a heavy loss to France to kick off their Qatar World Cup campaign. 

Already long odds to finish in the top two of Group D alongside the French reigning champions, Denmark and Tunisia, the Socceroos were not helped by a 4-1 loss to Les Bleus at Al Janoub Stadium.

It came on the back of a 0-0 draw between Denmark and Tunisia, leaving Australia last in the group after the first day of matches.

Paris Saint Germain superstar Kylian Mbappé was constantly threatening and played a part in three of France's goals, with fellow winger Ousmane Dembélé also influential and Olivier Giroud's double equalling Thierry Henry's record of 51 goals for France.

"They're world champions for a reason," Socceroos coach Graham Arnold said.

"The first half we did well, second half we ran out of legs a bit."

And it had started so well.

Australia shocked France by taking the lead in the ninth minute, when defender Harry Souttar unleashed Mat Leckie down the right wing with a sensational diagonal ball over the top, and Leckie's cross was poked into the top of the net by Adelaide United captain Craig Goodwin at the far post.

That might have given the Australians hope of emulating Saudi Arabia's upset of a global football power from mere hours earlier, especially as France lost defender Lucas Hernandez to a non-contact leg injury as he tried to stop the goal.

But it all seemed to awaken a sleeping giant, as France's world-class talent began to make an impact.

The pressure eventually told when, after reloading from a cleared corner, Hernandez's brother, Theo, crossed into the box and Adrien Rabiot nodded the ball past Mat Ryan.

Five minutes later, a costly turnover from Nathaniel Atkinson deep in Socceroos territory, followed by some neat interplay between Rabiot and Mbappé, led to Giroud's 50th international goal and a 2-1 lead for France.