Japan's final warm-up game for the World Cup finals ended in an unconvincing 1-0 win over Malta.
A second minute strike from Keiji Tamada gave Japan a victory, but the performance was well down on the impressive 2-2 draw against Germany a few days ago.
Coach Zico admitted: "We made a lot of mistakes. We didn't look good.
"We looked good against Germany the other day and couldn't win, but this time we looked bad and won. We want to learn from this."
Captain Tsuneyasu Miyamoto agreed with that sentiment, adding: "We could have played better.
"But we're on track and want to get better from here on in."