Arsene Wenger knows his players can improve following their Champions League collapse but also questioned the role of fifth officials as Arsenal let a three-goal lead slip.
Anderlecht came from 3-0 down to rescue a point in their Group D clash at the Emirates Stadium.
Anthony Vanden Borre struck twice for the visitors before Aleksandar Mitrovic's last-gasp leveller, but the first goal was clearly offside.
"We can learn a lot from what happened on Tuesday," Wenger said this morning. "We have special incidents. Some things we can correct, like the second and third goals. But we cannot influence the first goal. When the goalscorers are one yard offside, we cannot influence that.
"Every time we go to Geneva, (Pierluigi) Collina (UEFA's chief refereeing officer) explains to us that the fifth referee is a fantastic finding.
"But when you see the pictures on the first goal, it is unbelievable. A guy stands behind the line in front of the offside guy and does not stay a word.
"I do not know what the guys behind the line are paid for."