Brazil coach Carlos Alberto Parreira claimed his side's disappointing display in their first game at the World Cup finals was due to an excellent defensive performance from Croatia.
A stunning long-range strike from Kaka just before half-time earned the holders a 1-0 victory in Berlin, but their performance did not suggest they are good enough to retain the trophy.
However, Parreira said: "The challenge is not only the first game.
"In addition to the fact that the team hasn't played a lot together, we faced an adversary that was good and marking very well, with energy.
"I think the game was balanced, we had more shots on goal but we had a certain difficulty imposing our own rhythm.
"The result was exceptional, excellent. The performance could be better but it will improve in the next game. For us today it was so important to start with a win."
Croatia boss Zlatko Kranjcar was also in an upbeat mood after the game and insisted his side had shown they are good enough to beat Japan and Australia and progress from Group F.
"Brazil made a goal from just the one chance. This defeat won't stop us from going further," said Kranjcar.
"But they have fantastic players in their side with the likes of Kaka."