Jelavic, who is likely to be replaced by Mario Mandzukic for the game, is confident that his side can earn all three points against the Indomitable Lions.
"We must forget as soon as possible about the game against Brazil, not talk about it and focus on our game against Cameroon," Jelavic told the press.
"I didn't watch the Mexico vs. Cameroon game, only the first part but we are better than Cameroon in every position and will win.
"It makes no sense to talk about Brazil, we must forget that game."
Jelavic has scored six goals in 33 appearances for Croatia.