The La Liga champions went down 2-1 to the newly promoted side ahead of their Champions League tie with Celtic
Barcelona manager Luis Enrique accepts the responsibility remains with him after the La Liga champions suffered a shock 2-1 defeat to newly promoted Alaves.
Acosta Deyverson gave the visitors the lead before Gomez Ibai notched the winner just after the hour-mark and pseaking after the game, Enrique insisted that the buck stops with him.
"I am the one ultimately responsible for all the bad things that happen," he told BBC.
The defeat comes three days before Barcelona host Celtic in their opening Champions League group game on Tuesday night and Celtic come off the back of a 5-1 victory over fierce rivals Rangers in the first Old Firm of the season.
"Many of the changes came from the circumstances surrounding us, but we have 22 players and we are going to use everyone this season.
"We lacked fluidity, precision and we were fragile in defence, which is one of the things that normally makes us strong."