Barcelona star Jules Kounde pounced on his mistake in their 2-2 draw The League pull to Celta Vigo.
The Catalans missed the chance to extend their lead at the top of the table as they gave up a two-goal lead in the final five minutes in Vigo.
Despite looking confident over the line for victory in Galicia, complacency cost Barcelona, with Kounde particularly culpable.
Kounde was caught in possession on the edge of his own box in the build-up to Alfon Gonzalez's goal – which made it 2-1 on the night – as the Frenchman lost while trying to pass.
In his post-match interview, Kounde was clear in his assessment of the situation, as he tries to move on.
“We didn't do what we needed throughout the match and in the end we were punished. Starting from me, I didn't play a good game. I lacked concentration. In a very simple passage of the game, I made a very big mistake,” he said at full time.
“We have to return to our level. When things are going well, it is easy. Now we must be united and return to our best.”
Kounde and his Barcelona teammates have just a small turnaround window in the coming days as they prepare to host Stade Brest in UEFA Champions League action on November 26, with nine points from four games until now.