Las Palmas stunned Barca 2-1 at Montjuic, with Raphinha scoring the host's goal.
He later said: "We were bad in the game. We have to look at what we are doing wrong to try to improve and win games.
"We have dropped the level of what we were doing and this is making the games more difficult for us. We have to keep working and improve. We have to turn this around and get back to winning in LaLiga.
"I don't care about the goal, I cared about the victory. We didn't win and I'm not satisfied with the match. Am I angry? Yes."
On Las Palmas' tactics, Raphinha also said: "I don't want to talk about it because they can use it against me and punish me. But in the second half, only 30 minutes were played instead of the 45 required. They know what they're doing better than I do."
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