Two-legged tie
In sport (particularly association football), a two-legged tie is a contest between two teams which comprises two matches or "legs", with each team as the home team in one leg. The winning team is usually determined by aggregate score, the sum of the scores of the two legs. For example, if the scores of the two legs are:
First leg: Team A 4–1 Team B
Second leg: Team B 2–1 Team A
then the aggregate score will be Team A 5–3 Team B, meaning team A wins the tie. In some competitions, a tie is considered to be drawn if each team wins one leg, regardless of the aggregate score. Two-legged ties can be used in knockout cup competitions and playoffs.
In North America, the equivalent term is two-game total-goals series.
Use
In football, two-legged ties are used in the later stages of many international club tournaments, including the UEFA Champions League and the Copa Libertadores; in many domestic cup competitions, including the Coppa Italia and the Copa del Rey; in domestic league play-offs, including the Football League play-offs and the MLS Cup Playoffs; and in national-team playoffs in some qualification tournaments, including FIFA World Cup qualification.