Barcelona's poor start to the season continued on Wednesday evening as they went down 1-0 away to Rayo Vallecano.
Former Manchester United and Chelsea forward Radamel Falcao scored the lone goal as the Catalans suffered their fourth loss in ten games.
Barcelona could have left with at least a point, but Memphis Depay missed a penalty.
The loss, coming after the 2-1 home loss to bitter rivals Real Madrid last time out, leaves the Catalan club ninth on the standings with 15 points, six off leaders Sevilla.
Pressure has been piling for Ronald Koeman and will hope to turn things around in the coming games.
They next host Alaves, before an away clash against Dynamo Kyiv in the Champions League.