France have major doubts over two of their best players ahead of their World Cup quarter-final clash with Wales.

Scrum-half Antoine Dupont and winger Damian Penaud both sat out training in Oita amid growing concerns over their fitness.

Toulouse star Dupont has been complaining of a back problem for a number of weeks, according to French media reports.

He hasn’t taken part in training for the past couple of days and is a real worry for Les Bleus as they prepare for next Sunday’s last eight clash at the Oita Stadium.

Winger Damian Penaud has been one of France's outstanding players at the World Cup so far

There is also a worry over Clermont Auvergne speedster Penaud who has picked up a lower stomach strain ahead of the knock-out meeting with Wales.

If the free-running Dupont misses out, then Baptiste Serin would start at No 9, while Aliveriti Raka would be the man to step in for his Clermont team-mate Penaud.

Dupont appears to be the biggest concern, as his back injury has lingered for a while now.

The man who would come in for him, the Toulon-bound Serin, spoke to the media today and declared he was ready to start if required.

“There are training sessions this week then we’ll see how it’s going to be,” he said.

“I’m not in the head of the staff at the moment. But, individually, I’m getting ready and everyone wants to start such games.”

As for Wales, they are hoping to be able to pick from a fully-fit squad, with positive reports on the health of fly-half Dan Biggar (head knock), centre Jonathan Davies (knee) and wing George North (ankle).