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.”
Arsenal faced an uphill struggle going into Tuesday’s second leg having suffered a 5-1 defeat in Germany three weeks ago.
Theo Walcott’s first-half strike gave them a sliver of hope, but that vanished when Lewandowski scored from the spot shortly after the restart and Koscielny was sent off for the foul that led to the penalty.
Sidiropoulos initially showed Koscielny a yellow card but upgraded that to a red after consulting his assistant on the byeline, with the defender apparently deemed to have committed a deliberate foul.
Under laws introduced in April, the previous punishment of a red card and a penalty for a foul in the box that denies a goalscoring opportunity was changed.
Now, players committing accidental fouls that deny a goalscoring chance are shown a yellow instead – but deliberate fouls still incur a red card.
After Bayern’s equaliser, Arsenal’s momentum faded. They conceded four goals in 17 minutes but, despite suffering the biggest aggregate defeat of an English side in the Champions League, Wenger said the result did not “reflect the courage of the performance”.
“Overall it’s difficult to understand what’s happened,” he told BT Sport. “I still must say my team has produced a huge effort and played very well.”
Wenger added he thought Xabi Alonso’s challenge on Theo Walcott in the first half was “100% a penalty”, and also claimed Bayern striker Lewandowski was offside in the build-up to the foul by Koscielny that resulted in the French defender’s dismissal.
“It’s just not serious,” Wenger said.
“When you see the importance of the games and you see an attitude like that I am absolutely revolted and sorry for people who come and pay a lot of money to watch this kind of game.”
The 67-year-old Frenchman was also the subject of protests from fans before the game at Emirates Stadium, asking for him to step down.
When asked about the demonstration, Wenger said: “I’ve nothing to add to that.”