Xavi admits Barcelona's draw at Getafe was not good enough.
The result means Real Madrid are guaranteed to be top of the table at Christmas, while Atletico Madrid could go level on points with Barcelona if they beat Villarreal on Sunday.
"It's a step backwards. We tried it all in the kind of game we're used to facing, but if you can't break the deadlock things get difficult," said Xavi.
"We had three or four really good chances, especially the Messi free-kick onto the bar, but the ball didn't want to go in."
The eight-match winning streak has come to an end, and now "we have to get back to the good way things were going until now."