World Cup holders France will need Kylian Mbappe at his best in Qatar following the loss of Ballon d'Or winner Karim Benzema to injury, coach Didier Deschamps said on Monday.
France begin their defence against Australia on Tuesday as they look to move on from a troubled build-up which saw several key players pull out injured. Benzema was then forced to withdraw over the weekend.
The Real Madrid striker succumbed to a left thigh injury, although he played no part in France's 2018 triumph in Russia when Mbappe burst onto the world stage.
The Paris Saint-Germain striker was just 19 but scored four goals during that World Cup, including one in the 4-2 final win over Croatia.
"He is still a young player, just a bit less than four years ago, but he already did very important things four years ago," Deschamps told reporters in Doha.
"Since then he has become more mature and there is now even more recognition for him around the world.
"He doesn't have any more responsibility within the squad than he did before, but he has always had the ability to make the difference and we will need that.
"He has the ability to be decisive at any moment, unlike many other players."
Mbappe, who turns 24 next month, will lead a French attack in which Olivier Giroud is now expected to start in the absence of Benzema.
If four years ago in Russia Mbappe was still a teenager, he is now an established world-class talent and one of the best-paid athletes on the planet after turning down Real Madrid and agreeing a highly lucrative new contract to stay in Paris earlier this year.
Yet his last major tournament was disappointing, with Mbappe failing to score at Euro 2020 and missing the crucial penalty as France lost to Switzerland in a shoot-out in the last 16.
However, France captain Hugo Lloris insisted: "It is hard to say just how good he can be. He seems focused but also relaxed and he is eager to play well and help the team."
France also began their 2018 campaign against Australia and needed a late own goal to secure a 2-1 win.
The Socceroos come into this tournament among the rank outsiders after needing a penalty shoot-out to beat Peru in a play-off to qualify.
Graham Arnold's team is lacking players who are established at leading European clubs and Tuesday's game looks a mismatch, on paper at least.
"Above all else I think they are a competitive team and they will have grown in confidence since beating Peru on penalties. In general that is the kind of thing that brings a team together," said Lloris.
Deschamps confirmed that Manchester United centre-back Raphael Varane is fit to feature after recovering a leg injury.