Celta Vigo beat a much-changed Barcelona 2-0 at Estadio de Balaidos to take a big step towards securing LaLiga survial.
With the title long secure, Barcelona manager Ernesto Valverde opted to change the whole starting XI from the Champions League’s match against Liverpool, resting key players for next week’s second leg.
Ousmane Dembele, though, lasted less than 10 minutes before he was forced off with what looked like a hamstring problem.
Maxi Gomez broke the deadlock in the 67th minute before Iago Aspas wrapped things up with a late penalty, given for handball following a Video Assistant Referee referral.
Celta Vigo move five points clear of the relegation zone to 14th place, while Barca slipped to a first LaLiga defeat since November.
Maxi Gomez looked to get on the end of a long ball over the top, but his first-time volley flew wide.
In the 20th minute, Carles Alena had a chance for Barca after good work from Kevin-Prince Boateng to win back possession, but could only slice his 20-yard effort off target.
With Celta continuing to press, the visitors looked to slow the tempo down as the first half went on.
As the interval approached, Moussa Wague went forward from right-back before cutting inside and drilling in an angle shot which goalkeeper Ruben Blanco pushed away.
Celta threatened again from a corner when defender Nestor Araujo’s header flew straight at Barca keeper Jasper Cillessen.
The home fans thought they had made the breakthrough at the start of the second half when Araujo knocked the ball in after Cillessen had saved Gustavo Cabral’s header from a corner.
However, following a lengthy review by the Video Assistant Referee, the goal was ruled out for the narrowest of offside decisions.
Sofiane Boufal twice went close, first with a free-kick which curled just past the top corner and then with a rising effort after cutting in from the left.
Gomez headed a cross from Ryad Boudebouz straight at Cillessen, before the striker eventually found the back of the net in the 67th minute.
Shortly after Barca defender Jean-Clair Todibo had pulled up with what looked like a hamstring problem, Celta broke down the right through Boudebouz, who played Gomez into the box.
The striker held off substitute Arturo Vidal to clip the ball past Cillessen.
Following the goal, Barca were able to make another substitution as Jeison Murillo came on for Todibo, who had headed back to the dressing room after leaving the pitch.
Gomez remained a threat and curled his shot from the edge of the box wide after latching onto a stray pass from Samuel Umtiti.
With four minutes left, Celta appealed for a penalty when the ball looked to have hit Wague on the arm, but the referee waved play on.
Following a VAR referral and look at the on-pitch monitor, the spot-kick was awarded.
Aspas made no mistake from the penalty spot, sending Cillessen the wrong way to secure what could be a priceless three points in the battle to stay in LaLiga.