However, Sagna believes that the league leaders must not dwell on the loss for too long if they want to get back to winning ways.
"If we don't give the maximum and if you lose decisive challenges you put yourself in trouble and that's what happened during the first half," he told the club's official website.
"But I want to think positive, I want to keep looking forward, I want to think we are first and we want to stay first. The best way to do it is to respond well on the next game."
Arsenal return to Premier League action on November 23 when they welcome high-flying Southampton to the Emirates Stadium.