Japan coach Alberto Zaccheroni lamented his team's lack of intensity as they conceded two headers in three minutes to allow Ivory Coast to snatch all three points in their opening World Cup Group C game on Saturday.
"This morning the team was well, physically and mentally, and they started off well," the Italian told a news conference.
"I will have to analyse why they were unable to keep their performance level high."
Japan took the lead early in the first half through Keisuke Honda, but the introduction of Didier Drogba from the bench on the hour mark proved the catalyst for an Ivorian comeback, with Wilfried Bony and Gervinho scoring to turn the game around.
"Two goals in two minutes shows a lack of concentration," Zaccheroni said. "In the penalty area they are more physical and we should have prevented them from coming in and shooting freely in that position.
"We allowed their wide players to cross the ball in and should have done a better job in preventing that." Japan had no answer to the power and pace of the Ivorians.
