Japan coach Alberto Zaccheroni says his squad must not underrate their opponents in FIFA World Cup™ qualifying, although he believes the Asian champions have the potential to win the trophy one day.

"I want my team to be confident that they can come through. But we shall never make the mistake of underestimating our opponents," he said ahead of Japan's opening FIFA World Cup qualifier against Korea DPR at home on 2 September. "North Korea are fierce and so mentally tough that they don't give up," Zaccheroni told Japanese media on Monday.

I mean it when I say Japan have the potential to win the World Cup in the future. Japan know they have to grow.

Alberto Zaccheroni

"Uzbekistan played fine at the Asian Cup," except for their 6-0 semi-final loss to Australia, the 58-year-old Italian said. He added that he had no information yet about Tajikistan, who joined the group last week to replace Syria, who were disqualified for using an ineligible player in a preliminary qualifier.

Zaccheroni, who took over Japan after they reached the last 16 at the 2010 FIFA World Cup in South Africa, is undefeated after 11 matches with six wins and five draws, including a historic 1-0 friendly victory over Argentina. The Blue Samurai won a record fourth AFC Asian Cup title in January by beating Australia 1-0 in the final.

"All flattery aside, Japan have been developing well," said the former AC Milan boss, who spent all his coaching career in Italian club football before coming to Japan. "I mean it when I say Japan have the potential to win the World Cup in the future. Japan know they have to grow. The world's leading countries have stopped growing as they believe that they are at the top."