In sports (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:
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 home-and-home series or, if decided by aggregate, two-game total-goals series.
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 in national-team playoffs in some qualification tournaments, including FIFA World Cup qualification.
In ice hockey, the National Hockey League used two-game, total-goals series in the early years of its playoffs. It applied to all its playoffs from 1918 to 1926, and the early rounds until 1937, when it completed the switch to best-of-n series. The NCAA Men's Ice Hockey Championship also used a two-game total goals format for much of its history.
In rugby union, two-legged matches are used in the qualifying stages of the Rugby World Cup. The semifinals of the Italian National Championship of Excellence are also two-legged, as are the semifinals and final of England's second-tier league, the RFU Championship.
In basketball, the two top European club competitions, the Euroleague and Eurocup, both use two-legged ties in the qualifying rounds that determine the clubs advancing to each competition's group phase. The Eurocup also uses two-legged ties in its quarterfinal round, which will be a separate phase of the competition starting in 2009-10. The French Pro A league used two-legged ties in all of its playoff rounds, except for the one-off final, until the 2006-07 season. At that time, all of its playoff rounds leading up to the final, which remained a single match through 2011-12, were changed to best-of-three series. The final changed to best-of-five starting in 2012-13.
Other the seasons, Gaelic football, two-legged finals were used for five seasons of the National Football League, the last in 1988-89. The International Rules Series was also two-legged in 1998-2013 and from 2017 onward.
In Arena football, the playoff semifinals (but not the Arena Bowl itself) are decided, as of the 2018 season, by a two-legged total points playoff. In one 2018 semifinal, the first game ended in a tie, and went to overtime. However, the winner of the second game won by a larger margin (within regulation time) and was awarded overall victory based on total aggregate points.
If the aggregate score is tied after the two legs, various methods can be used to break ties. Under the away goals rule, the team who scored more away goals advances. If away goals are equal, or are not considered, then the tie may be decided by extra time and/or penalty shootout. Replays, at the second-leg venue or a neutral venue, were formerly used in European club competitions. In the Liguilla (playoffs) of the Primera División de México, the team with the better regular-season record advances; some leagues take the two teams' record against one another into account. In the promotion playoffs in Italy's Serie B (which do not necessarily occur in a given season), two-legged ties that are level on aggregate at the end of regulation time of the second leg go to extra time (away goals are not used); if the tie remains level after extra time, the team that finished higher on the league table advances.
Each team hosts one match, and there is no intended advantage to whether a team plays at home first or second. However, many managers and players believe that the team playing at home for the second leg has a slight advantage. The thinking is that the team playing away for the first leg can play it safe there (a draw or even a slight defeat is considered a favourable result), and then "win" the tie at home in the second leg.
A statistical analysis of roughly 12,000 matches from the European club competitions between 1956 and 2007 showed that around 53% of teams playing at home in the second leg won the tie (even after allowing for the fact that team playing at home in the second leg tend to be better teams).
In the case of World Cup intercontinental playoffs the team that plays the second leg at home has won 61% of ties.
In many competitions where two-legged ties involve seeded and unseeded teams, the seeded team are given home advantage in the second leg. For example, in the UEFA Champions League round of 16, the group winners play the second leg at home while the group runners-up play the first leg at home.
Until the 2016 edition of the Copa do Brasil, in the first two rounds which were played as two-legged ties, if the away team won the first leg by two or more goals, they would progress straight to the next round without needing to play the second leg which they would play at home. However, the second leg would still have to be played if the home team won the first leg by two or more goals.
In knockout competitions, alternatives to two-legged ties include: