France unfazed by early Aussie cup assault

France frontman Olivier Giroud was not fazed by Australia's ferocious opening to their World Cup fixture.

The Socceroos scored first and generally held sway for the initial 25 minutes at Al Janoub Stadium.

"We shouldn't have been surprised by the start," Giroud told reporters.

"We were aware about the determination of the Australian players.

"They played well at the beginning but most importantly we reacted straight away.

"We started the game not the best way but we showed great character and we bounced back."

Giroud scored twice in France's 4-1 triumph, taking his international career tally to 51 and equalling a record set by Thierry Henry.

"I feel blessed to have the opportunity to be next to Thierry now," he said. 

"I just try to bring what I can do to the team and when I get the opportunity, I try to put the ball in the back of the net.

"This time I couldn't miss, if I can say, because I received great balls."

But the 36-year-old striker said France's victory was soured somewhat by the injury sustained by star defender Lucas Hernandez.

The Bayern Munich left-back suffered cruciate ligament damage to his right knee when turned by Australia's Mathew Leckie in the build-up to the Socceroos' goal.

Hernandez has been ruled out of the cup and could face a year on the sidelines if a knee reconstruction is required.

"I am afraid it could be pretty serious," France coach Didier Deschamps said.

Hernandez's injury is the latest to hit France, who have also lost players including Paul Pogba, N'Golo Kante, Christopher Nkunku and Ballon d'Or winner Karim Benzema. 

But Deschamps was heartened by the way his players rallied after Australia's early strike.

"In the second half, we showed a lot more confidence and we forced Australia onto the back foot," he said.

"We created a lot of chances and scored four goals in total, so of course, that's good. We could have scored more.

"But it's a very good beginning to the tournament.

"The opening match is always vital, it's always important."