Brazilian striker Fred has learned from his mistakes at last year's Confederations Cup and vowed not to talk up his chances of scoring in the World Cup.

The Fluminense forward promised five goals in five games during last year's Confederations Cup and was criticized after a barren spell in the group games.

Even though he partly made good on his promise with two goals in the 3-0 final win over Spain, he said on Sunday he has learnt his lesson.

"When I went two games without scoring you guys almost killed me," Fred told reporters after Brazil's training session on Sunday. "I am going to change my tactics, I am not going to say anything so I can score goals in the World Cup too."

The big striker said he was working on other aspects of his game and lauded the support of manager Luiz Felipe Scolari, who brought him back into the international squad in 2013 after years in the wilderness.

"Felipao is demanding that I take less responsibility for just wanting to score goals, goals, goals and he's asked me to be more mobile and create spaces for Neymar and Hulk, to pull the central defenders out of position so they can score and that's what I've been working on," Fred said.

"My objective is to score goals, but if I don't then the bigger objective is to win games and trophies."

"Felipao took over and he loves playing with a center forward and he has given me the chance, even when I went through some bad spells. He showed faith in me in the Confederations Cup."

Fred said he expected a tough series of matches but warned that the tougher they are the more likely he is to play a part.

"I don't see a lot of the ball, I don't have the skills of Neymar, we fight, we hold up the ball, we open spaces," he said.

"But when the games get complicated the center forward is the one that is closest to goal and it's normal that he's the one the team looks for.

"I can't wait for the World Cup to start because I am sure that all the games are going to be difficult and I think that is good for a player with my style of play, one in which the team will look to me as a point man."

The Brazil team returned to its base at the Granja Comary outside Rio de Janeiro on Sunday after having 36 hours off following its 1-0 win over Serbia in Sao Paulo on Friday.

Brazil opens the World Cup on Thursday when it faces Croatia at the Arena Corinthians.

Mexico and Cameroon are also in Group A.