A late Gerard Moreno strike gifted the hosts a win over Zidane's side.
"Sometimes, you can't understand football," he confessed. "You have to accept the bad times.
"After five games of good results and good play, today we didn't manage it."
The coach believes that the performance warranted more than going home empty handed, despite Gerard Moreno's late winner.
"We didn't deserve the defeat," he insisted.
"Espanyol had few chances.
"It's a bad result."
When pushed on what was missing from the performance, he refused to single out any area in particular.
"A bit of everything," was his analysis.
"We started very well in the first half and we had chances, but didn't score.
"We didn't find our style of play or any depth in the second half."