Hidetoshi Nakata fears Japan could suffer a mental meltdown at the World Cup and has demanded a more professional attitude ahead of the Asian champion's Group F opener against Australia.
Japan coach Zico gestures during a training session on Monday in Bonn.
Japan travels to Leverkusen on Tuesday to face World Cup host Germany, which is riding high after a morale-boosting 7-0 win over Luxembourg, and then plays Malta in Duesseldorf on June 4 in its final warmup.
But Bolton Wanderers midfielder Nakata claims the mood in the camp is not what it should be with two weeks to go before Japan play Guus Hiddink's men on June 12, and says the less experienced players in the team need to show more professionalism.