Coach Luiz Felipe Scolari admits that a lack of experience is hurting Brazil's young squad at the World Cup.
The coach is also blaming the team's struggles, which include a disappointing performance that nearly led to its elimination by Chile in the second round, on the pressure of succeeding in front of the home fans.
Brazil has only six players from past World Cups, and some of its top stars, including Neymar, are playing in football's biggest stage for the first time.
"Of course it's a concern, we have a young team," Scolari said after Brazil's win over Chile in a penalty shootout. "Even the most experienced players will feel the pressure of a World Cup. Everybody feels it. If you say that you don't feel it, you are lying. It's a different situation emotionally, it's never simple. We have a lot of young players, and little by little they will gain more of this experience."
The coach used the example of young midfielder Willian, who is one of the team's best penalty takers in training but sent his shot wide in Saturday's shootout in Belo Horizonte. Scolari said "experience" likely played a role in his miss.
"We will be gaining more experience in each match we play," the coach said. "Hopefully, in the next matches we will be making fewer mistakes because of this lack of experience. We can't lose anymore."
Brazil will play South American rival Colombia in the quarterfinals on Friday in the northeastern city of Fortaleza.
Scolari said Brazil's disappointing second-half performance against Chile, when the team looked nervous and wasn't able to impose its game, can be blamed on the pressure felt by the players, who started feeling more and more anxious as the match neared its end and elimination became a possibility.
Only five players from this year's team were in the 2010 World Cup - Julio Cesar, Thiago Silva, Dani Alves, Maicon and Ramires. Fred didn't make it to South Africa but was in the squad for the 2006 tournament in Germany.
Scolari had been saying since announcing his squad that he didn't think the players lacked the experience needed for the World Cup. He said that despite their young age, most had been playing in some of the world's top leagues for a long time. Most also participated in last year's Confederations Cup, the warm-up tournament which Brazil won at home.
Scolari has always said that anything but the title will be considered a failure for Brazil, and has maintained since the start that his team will win the World Cup.
"People are demanding it from us," Scolari said. "Because we said we would win. Now we have to give it back to them. If you make a promise, you must deliver. This is what the players are doing."