France coach Didier Deschamps says he is instilling a combat mentality in his players ahead of their FIFA World Cup™ play-off against Ukraine.

France play their first leg in Kiev on Friday before hosting the Ukrainians at the Stade de France on Tuesday next week.

And even four days out from the first leg, Deschamps insists his players are already primed for action.

"It's played on the pitch but it's the head that manages the legs," the former Juventus and Monaco coach said.

"We're in a state of mind of 'challenge', of 'combat'.

"There's no room for doubt, for uncertainty, for questioning."

France reached the play-offs by finishing second to Spain in their group while Ukraine were edged out of top spot in their pool by England.

Ukraine were edged out by a single goal against Greece.

According to Deschamps it is aggression that will make the difference in such a sudden-death, knock-out stage.

"The players are competitors and we feed off that," he said.

"We can't be nervous or worried. The top level is about aggressiveness and commitment."