Barcelona coach Hansi Flick was hugely critical of his team's performance after the LaLiga leaders blew a two-goal lead to draw 2-2 with Celta Vigo at Balaídos on Saturday.
Goals from Raphinha and Robert Lewandowski either side of half-time had set Barça on course for three points, but Celta struck twice in the final six minutes, through Alfonso González and Hugo Álvarez, to earn a point after Marc Casadó was sent off.
Barça are now winless in two games having lost to Real Sociedad before the international break and they have failed to win any of their three league matches when Lamine Yamal, absent here through injury, has not started.
"Sometimes it happens that you see such a performance from a team," Flick said in a news conference when asked to explain his side's lacklustre display.
"I [didn't] expect that we [could] play really bad like that but it's like this. We have to stand up and go forwards. It's one match.
"At the end, the best thing was we get one point. It's the best thing about today, but we are not happy. The players are not happy, everyone is not happy, and I think everyone can play much better than today."
Despite trailing 2-0, Celta matched Barça for large parts of the game and registered six more shots on goal than their opponents throughout the course of 90 minutes.
However, it took Casadó's 82nd minute red card, awarded after he picked up a second booking, and a mistake from Jules Koundé for them to get back into the game.
Flick refused to blame either player for the result, though, and suggested his Barça side, who had won 11 of their opening 12 games before setbacks against La Real and Celta, had started to think it was too easy to win matches.
"Everyone said that Celta Vigo is difficult to play and you can see it today," he added.
"At the end, it has to do with concentration and focus. Maybe sometimes it was too easy or they think it's too easy to win, but it's not easy. Everyone now wants to win against us and wants to play good against us.
"There were a lot of mistakes, a lot of bad passes, losing the ball, wrong decisions and that. It's not about the red card. It's not about Jules' mistake. [It's about] the whole team.
"It's a result of how we played. We have to come back. When you are 80% or 85% or 90% you cannot win. It's not so easy like that."
Koundé took responsibility for his role in the draw, admitting he should have done better when messing up a back pass to goalkeeper Iñaki Peña in the 84th minute.
"We weren't at the level required for the whole game and in the end we have been punished -- starting with me, because I did not have a good game," the France defender told reporters.
"There was a lack of concentration on my part. In what should have been a simple play, I committed a huge error. That mistake has hurt us.
"It's a learning curve for everyone. We have not played well in the last two games. We have to get back to our level. When things are going well, it's really easy, but now we have to be united and focus on recovering our best form."
As well as Lewandowski and Raphinha netting their 20th and 13th goals of the campaign, respectively, there was some good news for Barça in the form of a first start in a year for Gavi.
The midfielder completed 75 minutes as he continued his return to fitness from the ACL injury he picked up last November, but he was disappointed with how the team threw the game away.
"I am happy to be starting for the first time in a year, but the important thing today was to get the three points and that's not been the case," he told reporters.
"We had the game controlled, but the red card completely changed things. Then, in two moves they've scored two goals. The first goal was silly, you have to clear the ball.
"And then with a man less it is difficult to keep the three points. It doesn't matter what team you are, if you're lacking concentration, this can happen. You've seen it here. We have to learn from this. We keep going."
Barça are five points clear of second-placed Atlético Madrid, but Real Madrid, currently third, could move within one point of them if they win their two games in hand, starting with Leganés on Sunday.