Brazil escaped tough opponents in the World Cup group stage in Friday's draw, but the hosts will probably face some major rivals as early as the second round.
Friday's draw put Mexico, Croatia and Cameroon in Group A along with Brazil, teams unlikely to keep the five-time winners from advancing.
But defending champions Spain or Netherlands await in the knockout stage if Brazil moves forward.
Manager Luiz Felipe Scolari praised his group opponents and said he didn't think Brazil were given an easy path to the round of 16.
"We can't worry too far ahead past the group stage," Scolari said. "If you start thinking about the second round you forget about the teams in the first round, which are important. We have worry about these teams first."
Scolari said he's happy to be facing Croatia in the opening game because European teams will likely take longer to adapt to conditions in Brazil.
"Europeans teams always take longer to adapt to the conditions in Brazil," Scolari said. "This first match is always difficult for all teams, but we live here, we work here, it's our country, so for us it's a little bit easier. In these first three matches it's important to get off to a good start."
Croatia boss Niko Kovac acknowledged his side face a challenge in the World Cup's opening game, June 12 in Sao Paulo, but says his players will be excited to be in the spotlight.
He said: "Now that we are in such a hard group then it is good that we are opening the World Cup against Brazil. It will be a great opening -- tiny Croatia against great Brazil.
"Brazil will be a special motivation for my players. It is now important for us to get ready the best we can, to play good football and satisfy our fans in Croatia. We will do everything to prepare for the opener against the hosts.
"This will be a chance for our little country to represent itself in front of a wide audience. We have half a year to prepare for something good.
"We are here to play nice football with a lot of passion. If that happens, we will go a long way in the tournament."
Brazil's second match is against Mexico and they close the group against Cameroon.
"Croatia has a beautiful game, Cameroon has done some great things against top teams in the World Cup and Mexico is always a tough opponent for us," Scolari said. "We have to prepare to play these matches and then we can think about the future."
Volker Finke, Cameroon coach, said it would also be tough for his team to play in remote Manaus.
"It's also a little bit of a problem to go in the north of Brazil in June," Finke said. "It's very, very hot and the climate maybe is difficult, but this is also difficult for both. We have to think again, maybe change a little bit the program because for me it was surprising to go to the north.
"But it's a draw, we have to follow. All the (Cameroon) players are in Europe and this is why it is also difficult to go here in this climate. It is very hot and we have to think about it."
Information from The Associated Press was used in this report.