Spain forward Pedro Rodriguez said Monday the world champions cannot afford any more mistakes following their shock 5-1 hammering by the Netherlands.

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."