The away goals rule is used to decide the winner in two-legged football matches when the aggregate score is even. Goals scored in a team's away leg count double, so for example the two results were Barca 1-2 Liverpool, Liverpool 0-1 Barca - aggregate score 2 - 2 over the 2 legs, but the game goes to Liverpool as they scored 2 away goals and Barca only scored 1 away goal. This rule takes priority over extra time and penalties.

If an aggregate score after the 2 legs is, for example 1 - 1 with both teams scoring away from home, then it goes to extra time and if still 1 - 1 then it will then go to penalties.