Cameroon coach Volker Finke has called for his team to step up to the tough task at hand as they prepare for their do-or-die clash against Croatia in Manaus on Wednesday.

Despite a series of refereeing blunders which favoured Cameroon, a goal by Mexico striker Oribe Peralta in the 61st minute sent them to defeat in their opening Group A match.

The defeat leaves them in third place ahead of their opponents, Croatia, who are bottom on goal difference.

Nevertheless, Finke is wary of the threat that Niko Kovac's men pose, and has rallied his troops to bounce back from a disappointing result.

"We must be ready to face the challenge," he said. "There were positives (in the last match); we were able to create chances and played some good football.

"They (Croatia) have great players plying their trade in Spain and Germany and we must remain very cautious even if we both lost our first game.

"But in football, the worst thing you can do is call everything into question. That doesn't work. In my opinion, you can't succeed like that. Doubts will drive you crazy. They lead to other doubts and you can't perform well when you start having doubts.

"It doesn't help to talk any more, we must just win to remain in the competition. When you lose the first match, you have to pick up maximum points in the second to remain in the hunt."

Their hopes of qualifying have been dealt a significant blow, with star striker Samuel Eto'o admitting that he will need "a miracle" for there to be any chance of him playing against the Croatians.

Despite featuring against Mexico just days ago, the 33-year-old claims that he felt discomfort in his knee as early as the ninth minute, and subsequently was unable to attend training.

"I am hoping the gods grant me a miracle and that I am able to defend my dear, beautiful country," Eto'o told Cameroon Radio-Television (CRTV).

"If this is not the case, I will always play my role as captain and especially as the big brother to push my young team-mates to victory."

Despite suffering a controversial 3-1 loss to Brazil, Croatian striker Nikica Jelavic believes that the team's quality will be enough to overcome a depleted Cameroon side.

The 28-year-old is expected to start on the bench, with Mario Mandzukic expected to return to the starting line-up after serving out his suspension.

"We must forget as soon as possible about the game against Brazil, not talk about it and focus on our game against Cameroon," he told reporters at a news conference.

"I didn't watch the Mexico v Cameroon game, only the first part, but we are better than Cameroon in every position and will win."

Their attempts at progressing from the group into the knockout stages will receive a timely boost with news that Real Madrid midfielder Luka Modric is a near-certain starter.

Asked about the chances of Modric featuring on Wednesday, team doctor Boris Nemec told reporters: "Greater than 90 per cent. Therapy is common, ice and stretching, but we cannot force him."