Mexico are ready to take on five-time champions and tournament hosts Brazil after overcoming two controversially disallowed 'goals' to beat Cameroon in their World Cup opener, coach Miguel Herrera said on Friday.

Herrera, who took over last year after a succession of coaches departed, said the 1-0 victory after two Giovani dos Santos efforts were ruled out shows the mental fortitude needed to make a deep run at the finals.

"The team overcame the disallowed goals," Herrera said. "The team showed they were mentally strong."

"The players were concentrating and if we maintain it on the pitch and continue to play football like this we can overcome anything."

In pouring rain and cheered on by a stadium full of their supporters, Mexico broke through after 61 minutes when Oribe Peralta rifled home a rebound from man-of-the match Dos Santos to secure the victory.

Mexico next face Brazil in Fortaleza on Tuesday in their second Group A match while Cameroon take on Croatia a day later in the jungle city of Manaus.

Cameroon's German coach Volker Finke declined to use the waterlogged pitch and driving rain as an excuse for the loss, saying his side created enough chances at the Dunas arena to get a result.

"The conditions are the same for both teams so we can't complain about the weather," Finke said. "The pitch itself wasn't too bad. It's a pity we didn't win but both teams had balanced chances."

Mexico's Herrera also admitted he was nervous about whether Peralta's strike would stand but said he would not worry about the refereeing going into the next match.

Brazil beat Croatia 3-1 in the opening game in part due to a contentious penalty awarded to the tournament hosts.

"No we are not thinking of the referee," Herrera said. "We are thinking of what we have to do. People make mistakes.

"The first two goals were very good goals. I was hoping we could have a goal. When we scored the first thing I was looking for was the linesman's flag."

Former national team player Herrera also said the tens of thousands of fans who roared their support throughout the game despite the rain would provide a big boost to El Tri throughout the finals.

"Our fans our extraordinary," Herrera said. "They sell their homes and their cars and their grandmother's old clothes to come to Brazil. They made us feel like locals and it seemed as if were playing in Azteca stadium in Mexico."