Arsene Wenger said he was “revolted” by the referee after his “brave” Arsenal side suffered a last-16 Champions League thrashing by Bayern Munich.
Referee Anastasios Sidiropoulos denied the hosts a penalty when 1-0 up before later awarding one for a Laurent Koscielny foul on Robert Lewandowski.
Koscielny was sent off as Arsenal lost 5-1 on Tuesday and 10-2 on aggregate.
“The penalty and red card are absolutely unexplainable and scandalous,” Gunners boss Wenger said.
“It’s irresponsible from the referee. It leaves me very angry and very frustrated.”