Japan coach Alberto Zaccheroni has conceded his side have much work to do ahead of their FIFA World Cup opener against Ivory Coast.
Zaccheroni's men were able to record a fifth victory in succession when they faced Zambia on Friday in their final warm-up friendly.
However, Japan had to come from two goals down before eventually running out 4-3 winners courtesy of an injury-time winner from Yoshito Okubo.
"Obviously we can't carry on like this," said Zaccheroni, whose side also gave up the first goal in a 3-1 triumph over Costa Rica earlier in the week.
"I'm thinking about the things we need to put right. The result wasn't important but the performance was.
"I told the players before the game that we have to sort out these problems in the next week. This team has its own logic. The players have followed that logic and played so well in the past but tonight we didn't have it.
"If the team knows what it should be doing then the chances of us winning are high, but if they veer away from that there is a bigger possibility of us losing. In today's game it was the latter."
"We didn't have that team logic but still won, so in that sense I am not satisfied."
Japan face the Ivory Coast on June 14 in Recife, before facing Greece and Colombia in their other Group C fixtures.