Spain goalkeeper Iker Casillas has admitted that the European champions were "nervous" as they struggled to overcome a stern Croatia side.
La Roja topped Group C following their 1-0 win, but Casillas has called on his teammates to improve if they are to retain the trophy.
"We had to suffer, but it's normal. There's not a single weak rival, and everyone who plays against Spain give the 100%. We've been good taking advantage of the situation," the 31-year-old told Telecinco.
"It was difficult because we went all nervous. With an isolated action we would have been out. Now we have got a life or death game, and I think that's not bad at all."
Casillas has 134 international caps to his name.
