Rougerie celebrates a try (Getty Images).

French coach Bernard Laporte extended his congratulations to Japan after the Cherry Blossoms put up a heroic show in Townsville.

France eventually emerged from their Pool B encounter with a 51-29 triumph - but not before they had been stunned by a Japanese rally which at one stage early in the second half saw the deficit reduced to just a single point.

"You have to congratulate Japan," said Laporte.

"They had lots of speed and agility and put us under a lot of pressure.

"I had felt quite confident in the first half - but in the second they put us under a lot of pressure and forced us into a lot of mistakes."

Although France managed to collect a vital bonus point for the second successive game, Frederic Michalak - who scored 24 points - suffered a suspected broken rib and influential lock Fabien Pelous took a heavy blow on the thigh.

Both are rated doubtful for next Saturday's crunch encounter with Scotland, in which Laporte must hope his team do not repeat this sloppy performance.

Aurelien Rougerie scored two tries for the French - while Pelous, Jean-Jacques Crenca, Michalak and Christophe Dominici also crossed for scores.

George Konia and Daisuke Ohata scored tries for Japan, and Toru Kurihara kicked five penalties and two conversions.

"I can't say it's good that we lost - but we are a lower-ranking side and we have helped Japanese rugby by making France struggle," said Japanese captain Takuro Miuchi.

"Our side has plenty of ability in all positions and now we have proved it against both Scotland and France."

He added he was delighted with the support Japan received at the Dairy Farmers Stadium and asked for more of the same when they take on Fiji - a contest they have a good chance of winning.

"I would like to send a sincere thank you to the Japanese fans who have made long trips and I would also like to thank the local fans who came to watch us play Scotland and wanted to come again," said the openside flanker.

"We never expected to see so many national flags as we did. It is also the first time I have ever experienced all the people around a stadium behind us. We want the people of Townsville to come along to the Fiji match and give us a big cheer."

Japan fly-half Andrew Miller paid tribute to his side's determination, saying: "I don't know where that (performance) came from ... we've got a lot of guts. We wanted to attack ... we did manage to turn over the odd ball. The French have got a couple of big boys.

"We were unfortunate to lose the game but we were happy to perform against such a strong team as France. At half-time we said we should never give up and we didn't. Now we must keep the momentum going."