Vicente del Bosque's men suffered a 5-1 loss to the Netherlands in their Group B opener, putting their title defence in disarray.
A loss to Chile in Rio de Janeiro on Wednesday and the Netherlands taking something out of their clash against Australia and Spain's tournament will be over.
Pedro was unable to say if he and his team-mates were anxious but they know the Chile game is their final opportunity.
"I don't know if there's anxiety but we only have one chance," the Barcelona attacker said.
"It is a final and we really have to prepare well mentally because we can't fail again.
"We have to play a great match against Chile, who are very difficult to play against, very compact with players who play with that intensity.
"We will try to prepare well and win the match, because we don't have another opportunity."
