Spain's undistinguished record of failure in the World Cup is threatening to strike again after an improbable 1-0 defeat to Switzerland gave the World Cup its first authentic shock. No side have won the competition after losing their first game and Spain's manager, Vicente del Bosque, described himself as "very upset" as he reflected on the potential ramifications.

"It's not a good omen and it's not a good sign that we have sent out to the other teams and the football world," Del Bosque said. "We have to face the next games and try to win them now. That should be our spirit because we can't drop our heads and think we were unfortunate or that we had bad luck – not when we still have the chance to put it right."

• Follow the Guardian's World Cup team on Twitter• Sign up to play our great Fantasy Football game• Stats centre: Get the lowdown on every player• The latest team-by-team news, features and more

Spain, whose previous best in the World Cup dates back to a fourth-place finish in 1950, will almost certainly have to beat Chile and Honduras in their remaining Group H games to qualify for the first knockout round and, if they finish runners-up, it sets up the possibility of an encounter with Brazil, pitting together the two pre-tournament favourites.

The Euro 2008 winners dominated possession but lost to a breakaway goal from Gelson Fernandes after 52 minutes. "It wasn't the best goal I have ever scored but it was certainly the most important," Fernandes said. "To be fair, I'm not used to scoring goals, so it's a special moment for me, one that will probably sink in later. It's a historic goal."

The former Manchester City player added: "We had a bit of luck because Spain had most of the possession and, technically and tactically, they're a very strong side. But I think we deserved that luck because we really couldn't have worked any harder."

A demoralising day for Spain was exacerbated when the midfielder Andrés Iniesta aggravated a thigh injury and limped off with 13 minutes to play, although Del Bosque said the first indication was that it was not serious enough to put him at risk for the remainder of the tournament.

"The simple fact is that everything went in favour of Switzerland," Del Bosque added. "We are upset but it has to make us even more determined for the next group games."