Fukuoka - French coach Jacques Brunel admitted Wednesday his team struggled to control the game in their 33-7 win against the USA, pointing his finger at the humidity and the referee.

The final score in the Pool C encounter flattered Les Bleus slightly, with three late tries securing the bonus point after the Eagles were only three points behind with just over 10 minutes remaining.

"We struggled for sure, especially physically because it was very humid," Brunel told reporters.

"We made quite a lot of handling errors. We did not control the game well but it's positive because we got the win and five points," added the coach.

France were penalised 10 times -- seven times in the first half -- and their indiscipline meant they never really imposed their free-flowing brand of rugby on the game.

"We started relatively well, we scored from some kicks, then we got a bit carried away. We stopped applying pressure and we were up against a solid defence," said Brunel.

The coach said he felt the referees had penalised his side more than the Eagles. "It's possible there were fouls but they were not penalised much in the rucks," he complained.

"And the illegal protection of their players in the mauls caused us quite a lot of problems."

The bonus-point win for Brunel's men keeps up the pressure on their eternal rivals England in the so-called 'Group of Death' which also includes Argentina.

France and England -- a match commonly known as "Le Crunch" -- takes place in Yokohama on October 12 but Brunel insisted he was looking no further than the next game, in four days against Tonga.

"We're not thinking about England, definitely not... the only goal is Tonga."

Louis Picamoles, who was captaining France for the first time in his long career, admitted it was a "difficult" match for his side.

"Lots of things didn't work well. We lost the plot a bit, let a lot of balls slip," said Picamoles.

"But we didn't panic and the freshness and support off the bench was good for us and enabled us to get the attacking bonus point" for four tries.