Toulouse — France captain Charles Ollivon said Sunday's 35-17 victory over Japan helps "grow confidence" as they continued their winning run before next year's World Cup on home soil.
Wing Damian Penaud crossed twice as Les Bleus claimed a 13th straight success less than 10 months out from the tournament.
Along with the only team above them in the world rankings, Ireland, Ollivon's outfit are leading contenders for the competition with the two countries meeting in the Six Nations in February.
"Not everything was perfect," Ollivon told France Television.
"We keep the series going and growing in confidence.
“It's a great way to prepare for the Six Nations.”
With the hosts of the next World Cup meeting the home country of the last edition, coach Fabien Galthie was forced into three changes including handing scrumhalf Maxime Lucu his 11th Test appearance.
Galthie's counterpart Jamie Joseph brought in a fresh half-back combination after last weekend's heavy loss to England.
Heavy rain started to fall seconds after the anthems in front of a sold-out 34-000 capacity Le Stadium in Toulouse.
The home crowd had something to celebrate despite the downpour after just seven minutes as Penaud made the most of Ryoki Yamanaka’s mistake in his own in-goal area.
Toulouse fullback Thomas Ramos then made up for missing the conversion by slotting two easy penalties and the home side led 11-0 after 17 minutes.
Brave Blossoms flyhalf Seungsin Lee, brought in after last Saturday's hammering at Twickenham, opened his team’s account on the quarter mark with a shot at goal to make it 11-3.
The rain stopped, but the pitch and ball were left slippery before Ramos added a third penalty just after half an hour as Galthie's team led 14-3.
France extended the advantage as Lucu set-up Ollivon, the pair coming from the same Basque village of Saint-Pee-sur-Nivelle, to slide over and they were 21-3 up at the break.
Less than 80 seconds after the interval Japan reduced the deficit as scrumhalf Naoato Saito crossed following centre Shogo Nakano's 40m break.
Lee converted to bring the score to 21-10 with 38 minutes left, but their hopes of a comeback were short-lived.
Galthie brought Matthieu Jalibert on from Romain Ntamack just before the hour mark and the replacement flyhalf's break from a chip kick down the right led to Penaud's second try of the game and his 19th try in 37 Tests.
Ramos slotted the extras as the sun threatened to come out with the home team leading 28-10 with 18 minutes to play.
Japan, ranked 10th in the world, refused to go down without a fight as wing Siosaia Fifita crossed and Lee converted the additional points to make it 28-17 with a quarter of an hour left.
The smart move from the back of the lineout leading to the try highlighted what the people of Toulouse can expect at next year's World Cup, with Japan playing two group games in the town.
France sealed the win with seven minutes to play as flank Anthony Jelonch crossed after another Jalibert chip, before Ramos kicked the conversion to take it to 35-17, as eyes turn to the defence of their Six Nations title, with just nine games to go until the World Cup.