Antoine Griezmann lit up Euro 2016 as France reached the final on home soil, but a series of stuttering performances at the World Cup have set alarm bells ringing ahead of a last-16 meeting with Argentina's Lionel Messi.
The Atletico Madrid striker looked far short of his best during the group stage, failing to complete a full 90 minutes in any of France's first three games.
Olivier Giroud suggested Griezmann was not at his physical peak after a long season in which he made a combined 60 appearances for club and country, culminating with victory in the Europa League final.
His teammates have rallied around him, led by Paul Pogba, a player subjected to his own fair share of criticism in recent months.
"Don't touch my Grizou," Pogba said with a smile last week. "You've forgotten the Euro."
A tired Griezmann also made a sluggish start at the European Championship, toiling initially before making his mark with a late goal in the 2-0 group win over Albania.
He led the French charge from that point onwards, scoring five of his six goals in the knockout rounds to finish as the tournament's top marksman.
"Just because he didn't score in the last match doesn't mean he's not the same Grizou," Pogba said after the 1-0 win over Peru.
Griezmann himself admitted he was hoping for more as a vastly talented France side attempt to fulfil their potential in Russia.
"I hope to raise my level again in the last 16," he told French television following the turgid 0-0 draw with Denmark.
"It was the same at the Euro. It wasn't until the last 16 that I hit my stride. So we'll see. I have confidence in my game."
Griezmann's decision to pledge his future to Atletico, despite strong interest from Barcelona, in a televised documentary two days before France's opening game provoked amusement within the team camp.
Silence the doubters
The 27-year-old insisted the drawn-out episode was not a distraction, although it was unusual for an Atletico representative to fly out to France's training base for Griezmann to sign his new deal.
"He's fine. You should never doubt one of the best players in the world," said France left-back Lucas Hernandez, a teammate of Griezmann's in Madrid.
"Here's hoping he shuts up everyone who is talking about him in the last 16."
Placing the blame entirely at Griezmann's feet would be unfair though, as the rest of France's attackers have also struggled.
Didier Deschamps has altered both his system and personnel during the tournament, with Griezmann winning and converting a penalty in a 2-1 victory over Australia but failing to link up effectively with Kylian Mbappe and Ousmane Dembele.
There was a better understanding with Giroud against Peru, but the pair lacked cohesion against the Danes and Griezmann did not complete a single pass to the Chelsea striker during the first half.
While Griezmann huffed and puffed, finding pockets of space, passes were often misplaced against a suffocating Danish back line.
"I felt good in the first half. I tried to drop back from time to time to pick up the ball," Griezmann said. "In the second half I tried to be closer to the area so I touched the ball less often, but that's the way I wanted to play."
After snubbing the chance to line up alongside Messi in Spain next season, Griezmann will look to trump the Argentine wizard in Kazan this weekend.
Goalkeeper Steve Mandanda fully expects his compatriot to win the duel with the Barcelona ace and breathe life into both his and his country's World Cup campaign.
"I know at any given moment, he's going to make the difference to enable us to get through," Mandanda said.