The European champions were supposed to be the Spanish squad that finally fulfilled their potential at football's international showpiece after decades of sides that flattered to deceive.
On Wednesday, however, their much-vaunted midfield and attack were neutralised by a solid Swiss defence, they conceded a scrappy goal and will now potentially face a second round encounter with five-times champions Brazil.
"This is of course not a good sign that we started off this way," Del Bosque told reporters. "I think our obligation is to cope with this situation and to face the next two matches by trying to win.
"This is our spirit and this will be our line for the next matches."
Spain play Honduras in Johannesburg on June 21 before rounding out their Group H campaign against Chile in Pretoria four days later.
CERTAIN STYLE
Del Bosque said the Swiss defeat was no cause for Spain to abandon the style of play that won them Euro 2008 and saw them lose just two matches in more than 3-1/2 years.
"We have come so far playing in a certain way," he said. "I would certainly not want to put anyone down and would simply say that we may not have shown our true personality as a team.
"We will do that certainly in the next two matches."
The good news for Spain is that all of their talented squad are fit, even if they could do with some shooting practice after missing a string of chances against the Swiss.
"We have a margin of error and we have used it up now," David Villa, who started Wednesday's match as a lone striker, told reporters. "That's football. The team that has the most chances doesn't always win."
"There's no way we are going to throw in the towel. We have to keep working and the fans should still believe in us."
At least the Spaniards no longer have to deal with questions about being tournament favourites with Brazil having replaced them with the shortest odds to win the final on July 11.
British bookmaker Ladrokes quotes 4-1 for Brazil to lift the trophy against 5-1 for Spain and Argentina.
"Playing your first match at a World Cup is always hard," goalkeeper and captain Iker Casillas told reporters. "All the more so when you are tagged as favourites."
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