Spain play Chile at Rio's Maracana Stadium on Wednesday knowing that anything other than a victory would likely bring a premature end to the defence of the title they won in South Africa four years ago.

"I don't know if there's anxiety but we really have to prepare well mentally because we can't fail again," said the 26-year-old Barcelona star at Monday's press conference in Curitiba.

"We have to play a great match against Chile, who are very difficult to play against, very compact."

Pedro, who came on as a substitute against Holland, is apparently being considered by coach Vicente del Bosque as a possible alternative to freshen up the starting XI in Rio.

Del Bosque had told Spanish television station Cuatro there could be two or three changes to the starting line-up and Pedro's pace would certainly be a plus against the nippy Chileans.

"The most dangerous thing is the intensity with which they play and how players such as Alexis (Sanchez), (Eduardo) Vargas and their full-backs stretch the game," added Pedro, who was a member of the 2010 World Cup and Euro 2012 winning sides.

"In midfield they have impact players like (Arturo) Vidal. It will be a difficult match but we know them well and we'll try to take the match to them."

So far in this tournament the teams that have been most atacking and positive have been rewarded, creating a thrilling World Cup full of goals.

It has led to question marks over Spain's patient possession approach but attacking midfielder Juan Mata insists it would be wrong to abandon the tried and tested tactic that has led them to the title in their last three major tournaments.

And he claimed they have already put their Dutch horror show behind them.

"These last few days we've focused on looking forward to the next match," said the Manchester United playmaker.

"We know what mistakes we made against Holland but we're thinking about Chile, about positive things, about improving.

"We need to continue with the style of this team, which is what has brought us success and in which we should have faith.

"We need to control the match and play the football that we're capable of and which has brought us success.

"I can't see any reason to change. We need to approach the two remaining pool matches like they're finals and be confident that we'll go through."