In June 2021, UEFA abolished the away goals tiebreaker starting with the 2021/22 season, and it proved to be a massive change that has altered the way coaches and players approach European competitions played over two legs.

Instead of away goals as a tiebreaker if teams are level on goals after 180 minutes (two legs of 90 minutes each), matches go into 30 minutes of extra time. And if that's not enough to decide a winner, the teams go to a penalty shootout to determine a victor.

In the past, away goals scored served as the first tiebreaker and only when teams were level on away goals did extra time and penalties become an option. The away goals tiebreaker rule was around for over 50 years (since 1965), but the European governing body UEFA indicated that it made the move to nix the tiebreaker based on sporting justice and feedback from the football community.

The first Champions League match to be affected by the rule change was a 2021/22 first qualifying round matchup between Welsh club Connah's Quay Nomads and Armenian side Alashkert, who went to extra time even though Alashkert had scored more away goals. Alashkert still advanced after scoring in extra time.

Since the rule change, there have been three penalty shootouts, all in the 2023/24 tournament. In the Round of 16, Arsenal edged past Porto and Atletico Madrid beat Inter Milan, before eventual champions Real Madrid knocked out Manchester City on spot-kicks in the quarterfinals.