Spain coach Vicente Del Bosque was critical of his side, despite the vital 2-0 win over Honduras.
David Villa scored both goals as the pre-tournament favourites bounced back from their shock defeat by Switzerland, but Del Bosque was left unimpressed.
"We didn't play a good game. We had a lot of chances and we should have won by more goals," he said.
"There were touches of quality but we were more vulnerable today than against Switzerland. I'm not especially happy."
Villa sunk Honduras with a spectacular first-half strike and a deflected effort after the break but Spain wasted several other opportunities, including a missed penalty from Villa.
The European champions are likely to need a win against Chile in their final group match to make the second round and Del Bosque looks set to again partner Villa with the fit-again Fernando Torres.
"Fernando is a great player. He has just recovered from an injury but he looks on top form physically. Let's hope in the next match he can do some more sterling work," stated Del Bosque, who was also impressed by his Central American opponents.
"Honduras were daring, although we did expect that. They have great players like Wilson Palacios, Amado Guevara, Noel Valladares - the spine of this team is very good."
Match-winner Villa, who would have become Spain's record World Cup goalscorer with six goals if he had completed his hat-trick from the penalty spot, appeared more upbeat than his manager.
"If we beat Chile we're practically group winners, the good thing is that we now depend on ourselves," said the striker.
"It's a shame [about the penalty]. I could have passed [the other four players on five goals] but I'm still happy with the result."
Source: BBC Sport