
Hansi Flick’s side needed to win their remaining three matches to reach that figure but fell at the first hurdle in Vitoria.
Ibrahim Diabate’s goal in first half stoppage time earned Alaves a vital victory in their battle against relegation, taking Quique Sanchez Flores’s team out of the drop zone and up to 15th.
Barca coach Flick gave 21-year-old centre-back Alvaro Cortes his debut, among several changes to the side that won the Clasico on Sunday to clinch back-to-back league titles.
The Catalans celebrated winning La Liga on Monday with an open-top bus parade and their performance reflected that to some extent.
Barca had plenty of the ball and winger Marcus Rashford offered energy, but Alaves dug deep to keep the visitors at arm’s length.
Just before the break Diabate fired past Wojciech Szczesny, after Antonio Blanco headed a corner back towards goal, with Barca defenders not reacting quickly.
Szczesny pushed away a Diabate strike early in the second half as Alaves tried to double their lead.
Barca struggled to create any clear chances and the hosts came close through Jon Guridi, who beat Szczesny but struck the post with a drive across goal.