Japan coach John Kirwan has urged the World Cup-bound Brave Blossoms to sharpen up their attack for their Pacific Nations Cup opener against holders Samoa at home on Saturday.
The Asian champions overwhelmed a hastily-assembled selection from the domestic Top League 49-7 in Tokyo on Sunday in a charity game for the victims of the March 11 earthquake and tsunami.
But the former All Blacks wing believes Japan need more offensive flair to improve on their previous Pacific Nations Cup results, which have left them bottom or next-to-last in the past five editions.
"If we think that today's going to be enough to win against Samoa then we're kidding ourselves," Kirwan told Japanese media after the match.
"Defensively we stuck to our patterns and got off the line and tackled well," said Kirwan, who has set Japan an ambitious goal of winning at least two matches at the Rugby World Cup in New Zealand - they have only won once in six previous editions.
"Our accuracy wasn't always as we would have liked," he added.
"We lost our structure in attack a couple of times and if we had been a little more patient we could have scored a couple more tries. It's back to work tomorrow."
Japan captain Takashi Kikutani scored a hat-trick of tries with Shaun Webb, Ryu Koliniasi, Ryan Nicholas and Yuta Imamura also touching down. Yasunori Nagatomo pulled one back for their opponents with eight minutes to go.
The Top League XV, who had only two training sessions, put more physical pressure on the Brave Blossoms than any side in the recent Asian Five Nations, in which they won a fourth straight title.
"We're trying to play a different style of game with our halfbacks becoming a big part of our attack, and you started to see that today," Kirwan told Kyodo.
"We need to work really hard to get some results at the PNC.
"Samoa, Tonga, Fiji have all reinforced their sides with European players so it's going to be a very difficult tournament for us."
Former Wallabies coach Eddie Jones, who coached the Top League XV, said Kirwan's squad played a "very physical game" but that he was not sure whether it would work against "more physical teams such as Samoa and Fiji".
"Their defence organisation was pretty good but playing that style of rugby, you're going to struggle to score points," the Suntory Sungoliath boss told Kyodo.
The Pacific Nations Cup tournament was originally scheduled to be staged in Japan, but five of the six games have been moved to Fiji after the March quake-tsunami disaster which sparked a crisis at a Japanese nuclear power plant.