Sevilla produced a brilliant second-half display to beat Barcelona 2-0 in their Copa del Rey quarter-final, first leg on Wednesday, leaving the holders with an uphill task to reach the last four.
After an even first 45 minutes, strikes from Pablo Sarabia and Wissam Ben Yedder stunned the Catalans and left them needing a second-leg comeback at the Nou Camp for the second consecutive round in the competition.
A much-changed Barcelona, who earlier in the day announced the signing of Frenkie de Jong from Ajax Amsterdam, handed a debut to loan signing Kevin-Prince Boateng.
Yet star forward Lionel Messi was left at home while forward Luis Suarez and club-record signing Philippe Coutinho were only named on the bench as they struggled.
"We were in the game in the first half and there were chances, but they pressured us more after the break," said Barcelona coach Ernesto Valverde, who said he had "no regrets" over resting Messi.
He added, "When you make changes, you take risks. If you win, then it's all good. If not, then it isn't. Last season we paid the price for going far in the cup and this year we're rotating more because we think it's the best thing to do. We want to keep our lead at the top of the league and use our squad members to help us."
Unsurprisingly it was Sevilla, spurred on by a raucous home crowd, who looked the more threatening throughout.
The Andalusian side were incensed when a Video Assistant Referee (VAR) review deemed that Barcelona's Arturo Vidal had not handled Ever Banega's cross after half an hour, with replays indicating the ball had struck the upper part of the Chilean's arm.
A persistent threat throughout, Ben Yedder fired narrowly wide after a mesmeric solo run, before being denied by a smart save from Barca keeper Jasper Cillessen.
At the other end, Malcom fired wide after rounding Sevilla keeper Juan Soriano against the run of play on the stroke of halftime.
It was all Sevilla after the break, and Pablo Machin's side took a deserved lead just before the hour.
Quincy Promes drove down the left before crossing for Sarabia, who fired in a half-volley from six metres out.
French forward Ben Yedder then doubled their lead from close range with a quarter of an hour to go.
He celebrated by lifting his shirt to reveal the message "For my brother Sala", in reference to Argentine striker Emiliano Sala, who is currently missing after the plane he was travelling on disappeared over the English channel.
The second leg takes place next Wednesday, while Espanyol take on Real Betis and Real Madrid host Girona on Thursday in the remaining quarter-final, first legs after Getafe defeated Valencia 1-0 on Tuesday.