In my opinion, Barcelona, along with Liverpool, the most in-form team in Europe right now. Therefore, their loss to Real Sociedad last night was a big surprise for me. Barcelona is still leading La Liga, but if Real Madrid wins, they’ll close the gap to 3 points. I believe that if Lewandowski's disallowed goal early in the match had counted, Barcelona would have won.
The better chance still remains 1-1
I know that Barcelona played the worst match of the season. But you are underestimating the mental factors in this game very much. If Barcelona got ahead then I think there would be a different game than we saw in the field. As a result this match is left behind and the thing Barcelona can do now is to learn their lesson from this match and focus on their upcoming matches.