Both teams won their opening FIFA World Cup matches, with Mexico accounting for Cameroon 1-0 and host nation Brazil defeating Croatia 3-1 in the tournament's curtain-raiser last week.
Victory for either country at the Estadio Castelao would all but secure a spot in the round of 16 ahead of the final round of group games.
Speaking on the eve of Tuesday's clash, goal-scoring hero Peralta insisted confidence is high in the Mexican camp and said the World Cup favourites were 'tough' but beatable on home soil.
"Thanks to the first win, we are very calm about the Brazil match, about taking another step forwards to achieving our goal," Peralta told FIFA.com.
"But the Brazil team is tough, very tough.
"We're going to make life difficult for them, because this game will be crucial. Still, it's a team that, if we play well, we can beat."
Peralta added: "After a difficult qualification, this team is clearly looking much better now.
"We have settled into a rhythm. And also, we have a lot of supporters here, following us and believing in us.
"This drives us on to give even more."
Mexico coach Miguel Herrera knows a much tougher encounter awaits his team than the one against Cameroon.
"Brazil is not Cameroon. They are the very favourites. They are the most important team at a worldwide level in football," he said.
"It is going to be a very hard match, but we are going to be a dignified opponent and we will fight for the three points."
