Arsenal manager Arsene Wenger says the away goals rule should count after extra time rather than full-time.
His side were eliminated from the Champions League by the rule after drawing 3-3 on aggregate with Monaco.
Arsenal lost 3-1 at home in the first leg on February 25 and went out after winning 2-0 at the Stade Louis II in Tuesday’s return fixture.
Wenger said: “The rule was created in the 1960s and the weight of the away goal is too great today.”
Away goals only count after extra time in the second leg of League Cup semi-finals, but are applied after 90 minutes in two-legged Champions League and Europa League ties.
They do not count in the Football League play-offs.
Chelsea were also knocked out of the Champions League on away goals and the Arsenal manager said the rule was “outdated.”
“Two English teams have gone out on away goals and that should be questioned.
“The rule was created in the 1960s to favour attacking teams but football has changed.”
Wenger said immediately after Tuesday’s second leg that Monaco did not deserve to progress.
Speaking on Thursday, the Frenchman said his team now have to “move on” from their fifth Champions League last-16 elimination in a row.
“We know why we went out – it’s down to a dreadful defensive performance in the first leg.”
“West Ham was a very physical game and we paid for it in the second half of the Monaco game. It’s a concern,” he added.