With the league title secured, the game sandwiched between crunch ties with Liverpool ends in only the third loss of the Liga season
For the fourth season in a row, FC Barcelona have failed to win at Balaidos, home of a Celta side that today needed the points much more than the visitors. The blaugrana already had the league title sewn up but still have to make sure of a place in the Champions League Final when they travel to Anfield midweek. The Galicians, meanwhile, were fighting for first division survival.
Ernesto Valverde had opted to leave several of his big names back in Catalonia, and there was an unfamiliar look to the side that took to the field, with Riqui Puig and Moussa Wagué of Barça B among the starters, and both shining brightly despite the scoreline.
The name of Alex Collado would soon be added to that list, with Ousmane Dembélé hobbling off with a hamstring injury after just six minutes and being replaced by the 20-year-old debutant.
Later in the game there was further French despair as Jean-Clair Todibo was also unable to complete the game.
Celta bag the points
Little was decided in a first half that never quite sprang to life. Jasper Cillessen, enjoying a start in the absence of Ter Stegen, was kept busy by Celta, if rarely seriously tested, while the Catalans best chance fell to Wagué moments before the break.
Grateful that Barça were without most of their biggest guns, Celta were desperate to seize the opportunity to get three points that would practically ensure first division survival and upped the ante after the restart.
They thought they had done it when a goal was disallowed for a very narrow, but correct, offside call, but did take the lead when Maxi Gomez converted a fine cross from Ryad Boudebouz.
And they would extend that lead when the VAR office spotted what the referee had not, a Wagué handball in the area. Iago Aspas converted the ensuing penalty and with just two minutes left on the clock, that was enough to put this game to bed.