France talisman Antoine Griezmann is looming as the Caltex Socceroos' trickiest group stage threat at the FIFA World Cup after continuing his exceptional club form.

But it wasn't all good news for Les Bleus over the weekend as an in-form attacking weapon's availability was cast into doubt after a clash with Caltex Socceroo Mathew Leckie.

And they're not the only Group C nation battling injury concerns, as we explore in this week's Opponent Watch.

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France

Griezmann continues to find form at just the right time, bagging a hat-trick and assisting another in Atletico Madrid's 5-2 rout of Sevilla.

The performance saw him become the second La Liga player, behind Lionel Messi, to reach double figures for both goals (16) and assists (10) in all competitions this season.

Griezmann's performance will have cheered Didier Deschamps following Kingsley Coman's worrisome ankle injury for Bayern Munich.

The winger suffered a partial tear of ligaments following a clash with Australia's own attacking outlet Leckie during a goalless draw with Hertha Berlin, and is set to miss "several weeks" after undergoing surgery, according to a club statement.

But there was good news for Paul Pogba, who was restored to Manchester United's starting side in the 2-1 defeat of Chelsea, and Paris Saint-Germain's teenage sensation Kylian Mbappe, owner of yet another Ligue 1 record thanks to his goal against Marseille.

Key defender Laurent Koscielny had a tougher time of it, captaining Arsenal to a limp 3-0 loss to Manchester City in the Carabao Cup final.

Denmark

Christian Eriksen is enjoying a rich vein of form at Tottenham and delivered again in a 1-0 win at Crystal Palace.

The playmaker supplied the cross for Harry Kane's winner, in the process becoming Spurs' joint-second provider of assists in Premier League history.

Speaking before the match, Eriksen said his team-mates were hitting top gear: "I don't know what it is about this time of year but it's probably all about how we train - we work hard, especially in pre-season and we really pick up this time of year."

Towering striker Nicolai Jorgensen isn't enjoying the same kind of form, having failed to find the net for an eighth consecutive competitive appearance in Feyenoord's 3-1 home loss against PSV.

Meanwhile, despite his error in last week's draw with Barcelona, Antonio Conte has earmarked Denmark defender Andreas Christensen as a future Chelsea captain, praising the 21-year-old's "great maturity".

Peru

Peru also received a major injury scare last week when first-choice goalkeeper Pedro Gallese went down with a knee injury on club duty.

He's expected to miss four to six weeks.

Star forward Jefferson Farfan is also on the sideline after sustaining a reported hamstring problem.

The Lokomotiv Moscow man limped out of the Europa League win over Nice and is in doubt for next Thursday's last-16 clash with Atletico Madrid.