Athletic Bilbao coach Ernesto Valverde offered no excuses after their 4-0 thrashing at Barcelona.
Valverde was particularly displeased with the Lions failure to trouble Marc-Andre Ter Stegen in the Barça goal.
The home side never gave Athletic a chance to get going, scoring the first three of their four goals within the first 22 minutes. Los Leones improved after the break but couldn't get back into the game.
"It was a horrible day. They were superior and it was a shock to the system. They punished us a lot," Valverde said after the match.
"In ten minutes they scored three goals and they really penalised us at every start. We had no chances because we hardly got into their box. We suffered a lot."
Valverde stressed it the importance of moving on as soon as possible, saying it was imperative Los Rojiblancos' make up for the loss against Villarreal CF at San Mamés next week.
He said: "When you lose, the most important thing is what you do after the match. We all make mistakes, we're not immune to having a bad day. Now we need to pick ourselves up before our next match."
