The Spain international feels the Blaugrana were in control prior to Athletic Bilbao's opener and has urged his team-mates to step up their game in front of goal
The Catalans were desperate to return to winning ways after their Champions League defeat against Ajax in midweek, but a single Iker Muniain strike after the break saw them leave the pitch empty handed once more, much to the 29-year-old's frustration.
"Defeats always happen for a reason, but I don't think we can compare this one with the game against Ajax. We had some good phases of play tonight, but we have to be more efficient," the attacking midfielder told reporters.
"We had the game under control, but the goal really hurt us. We put in a good first half and we played well at times after the break, but the goal really shook us and although we really tried, we couldn't come back.
"San Mames is always a tough place to come to."
Barcelona currently sit first in La Liga with 40 points from 15 games, with Atletico Madrid sitting second on goal difference.