Vicente del Bosque has admitted Spain must now win their remaining two games to reach the next phase of the World Cup after suffering a shock loss against Switzerland.
The European champions were stunned in their 2010 World Cup opener in Durban as Gelson Fernandes scored against the run of play in the second half.
Spain, who were considered favourites to lift the trophy prior to the tournament, must now look to bounce back against Honduras before tackling Chile in their final Group H match.
Del Bosque was disappointed for his players, who dominated possession, and conceded they must now fight tooth and nail if they are to qualify for the last 16.
"We tried in an orthodox way and in an heroic way but we were not able to source. It wasn't our day," said the Spain coach.
"We dominated almost all the match.
"This defeat means that we have to win the other two (group) matches."
He continued: "It was a match we tried to play without abandoning our style. We tried to play heroically and they fell back and tried to stop us."
"This is just the first match, everyone agrees that we have to fight to get out the group.
"No one in the team has ever talked about getting to the final or winning. We hit an obstacle and we'll get over it."
Spain defender Gerard Pique, meanwhile, admitted his team-mates struggled to truly test the Swiss, who were resolute throughout.
He said: "We had plenty of chances but they defended very well. I don't think we adapted adequately to their game."