France star Bernard Le Roux admitted they expected an easier match against the United States after battling to a 33-9 victory on Wednesday.

Three tries in the final 13 minutes secured a bonus-point win in Fukuoka that moves Jacques Brunel's side to within a point of Rugby World Cup Pool C leaders England.

The scoreline flattered Les Bleus, though, who led 12-6 at the break after a careless first-half performance and were pegged back to 12-9 before late scores from Gael Fickou, Baptiste Serin and Jefferson Poirot.

"I think we got a big surprise in the first half," Le Roux said after the match. "I think we thought it was going to be a bit easier but they stuck in there, they gave us a real hard time at the breakdown, we didn't get clean ball... it was really tough.

"We just didn't get fast ball. They were really contesting a lot of balls in the ruck, the phases didn't go well in the scrums, so yeah, they stuck in there and gave us a big surprise."

France's whole front row was changed within four minutes of the second half and Le Roux felt that helped his side regain some control.

"[The changes] made a big difference," he said. "We got some to go forward from the set plays and that opened up some space on the outside."

USA's Blaine Scully thinks the scoreline was an unfair reflection of their performance but is taking heart from the way they provided such a scare to a side ranked seven places above them in the world.

"We were in the game pretty much the whole way," he said. "The score got a little bit away from us at the end but I don't think that's necessarily indicative of the game out there.

"We were 100 per cent in this game and we wanted to put ourselves in a position to be there at the end. Unfortunately, [there were] a few too many turnovers our side, France are very dangerous from there and they punished us in those areas.

"It's where we want to be. We want to be testing ourselves in the best competition against the best teams in the world. We're asking no quarter and we don't expect them to give it to us."