Barcelona boss Ronald Koeman has said that his players 'lacked focus' and 'had a poor attitude' during Saturday's shock 2-1 loss to Cadiz in Spain's top flight.

The Catalan giants entered the contest off the back of three straight wins in all competitions but lost to a second-half effort from veteran forward Alvaro Negredo.

Seventh-placed Barca are now 12 points behind La Liga leaders Atletico Madrid, and Koeman has slammed his players for their performance against the promoted club.

"The defeat is difficult to explain. We've come here after some good games, but the first half wasn't good. We were better in the second half, but the way in which we lost was incredible," Marca quotes Koeman as saying.

"We lost due to an unexpected mistake that you cannot make. It came from not being focused. The attitude wasn't good tonight, and not just from the defenders.

"It's very hard to explain some of the goals that we've conceded. I think it might be because of a lack of concentration. We lack aggression without the ball. That might be why we concede. It's not easy to explain that second goal."

Barca will round off their Champions League group-stage campaign against Juventus on Tuesday night before hosting Levante in the league next weekend.