The captain has played down the suggestion that there is a great weight of expectation on the team's shoulders following its success in recent years.
Iker Casillas thinks Spain "have earned the right to fail" after dismissing the pressure of trying to win back-to-back World Cups.
The Real Madrid goalkeeper was part of the World Cup-winning side in South Africa four years ago, as well as the team that triumphed at the European Championships in 2008 and 2012.
Casillas will also likely be Vicente del Bosque's No. 1 in Brazil as Spain seeks to continue its recent dominance in international soccer.
However, the 33-year-old knows Spain — in a group that features Australia, Chile and the Netherlands — is just one of a number of teams with a realistic chance of winning the tournament.MORE: Top 25 infamous moments in World Cup history
"We have a difficult group. In addition, our first two matches are against (the Netherlands and Chile) who, in theory, we will be vying for qualification with," he said. "I think we need to go to Brazil without any pressure. In these last six years we haven't done good things, we have done sensational things. We have earned the right to fail.
"We are going with the idea of competing and defending our title, but we know that there are 31 other teams who want to do the same and it won't be easy."
Casillas believes Group B rival Netherlands could be a threat in the latter stages, noting that Spain's tough opener against Louis van Gaal's men will be a strong test.
"From what I hear from people, I think the Spanish fans are delighted with the last six years they have seen. The majority thought they would never see anything like it," he added. "We start against Holland, who should be the other big favorites along with us. However, I think that having to start strong gives us motivation. It means that the team must be in the right mindset from the first day."