Barcelona lost their first Primera Division match since Lionel Messi's injury as they slipped to a 2-1 defeat to Sevilla in a riveting game at the Sanchez Pizjuan.
Michael Krohn-Delhi gave the hosts the lead after 52 minutes and Vicente Iborra increased the advantage six minutes later, capitalising on awful defending from the Catalans.
Neymar pulled one back for Luis Enrique's side but, despite dominating the latter stages and hitting the woodwork three times over the course of the game, the champions could not find an equaliser and fell to a second straight away defeat.
Barcelona were ravaged by injuries going into this game, with Messi, Andres Iniesta, Rafinha, Thomas Vermaelen and Adriano all out, but Sevilla had a total of seven players missing, even though their manager Unai Emery remarked on the eve of the match that it was "the perfect time" to face Barcelona.
Claudio Bravo recovered from a thigh injury to make his first appearance in over a month and relieve the under-pressure Marc-Andre ter Stegen, while Javier Mascherano moved from defence to midfield alongside Sergio Busquets. Munir El Haddadi deputised for Messi and the in-form Sergi Roberto started ahead of Dani Alves.
The visitors' first attempt arrived after 10 minutes when Neymar skated clear of two Sevilla defenders to play in Luis Suarez, but Timothee Kolodziejczak got made a vital block.
Suarez then had an effort disallowed as the referee had already awarded a free-kick to Barcelona.
Neymar's effort from the set-piece cannoned off the inside of a post and the ball trickled along the goal line, evading Gerard Pique and coming to Suarez by the far post, but the Uruguayan's shot was blocked by Sevilla's Coke.
Suarez came close again on the stroke of half-time, curling the ball towards the far post with Sergio Rico stranded, but his shot struck the upright.
Although Barca had looked more dangerous on the break, Sevilla had been far from overwhelmed, matching their opponents in possession and strength.
And when they took the lead seven minutes after the break it was far from undeserved.
Kevin Gameiro exchanged passes with Grzegorz Krychowiak in midfield and then scampered down the right wing, passing Jordi Alba to get to the byline before cutting the ball back to the far post, where Krohn-Dehli arrived to slam it home with his left foot.
Barca did not cope well with going behind and nearly conceded again immediately as Krohn-Dehli released Gameiro in the area, but Pique got back to clear the danger.
But Barca's fragile defence was undone again shortly afterwards.
They were caught on the break and Krohn Dehli was able to chip the ball into Iborra, who, played onside by Jeremy Mathieu, rose to send a header beyond Bravo.
Barca came back at their opponents with a vengeance.
Neymar danced his way into the box, but his near-post drive was tipped behind by Rico.
The young goalkeeper thwarted the Brazilian again a few minutes later from close range, making himself big to swat the shot away.
The Catalans eventually found their way through via the penalty spot.
The kick was awarded when Benoit Tremoulinas blocked a shot from substitute Sandro with an arm right on the edge of the area and Neymar converted it, shooting powerfully into the bottom corner.
Barca almost completed the comeback a few minutes later when Suarez played in Sandro, but the youngster was denied by the near post and Sevilla held on to pick up just their second win of the campaign.