One-game playoff

A one-game playoff, sometimes known as a pennant playoff or play-in game, is a tiebreaker in certain sports—usually but not always professional—to determine which of two teams, tied in the final standings, will qualify for a post-season tournament. Such a playoff is either a single game or a short series of games (such as best-2-of-3).

This is distinguished from the more general usage of the term "playoff", which refers to the post-season tournament itself.

Major League Baseball
One-game playoffs are currently used in Major League Baseball (MLB). When two or more MLB teams are tied for a division championship or the wild card playoff berth (1995-2011, or starting in 2012, the second only) at the end of the regular season, a one-game playoff is used to determine the winner.

If a tie were, from 1995-2011, a two-way tie for a division championship and both tied teams' have records higher than those records of the second-place teams in the other divisions, or if the tie be (as of 2012) between the two teams who are guaranteed to clinch a wild card, there is no one-game playoff. In this scenario, the winner of the season series between the two teams is deemed division champion for purposes of playoff seeding (currently the #1 wild card that will host the game), and the loser of the season series is given the wild card (or in the current form, the #2 wild card). Through the 2008 season, home-field advantage for one-game playoffs was determined by a coin flip, but effective in, home advantage is based on a set of performance criteria, with the first tiebreaker being head-to-head record.

For statistical purposes, one-game playoffs are considered part of the regular season. The result of the playoff is included in the regular season standings and individual player statistics are included along with the statistics for the rest of the season. One significant playoff-like deviation from normal regular season games in force is that six-man umpire crews are used (as opposed to the four-man crews of the regular season).

The tie-breaking procedures become more complicated if three or more teams tie. This would require a series of one-game playoffs, taking more than one day. There have been several occasions where this scenario was possible as late as the last game of the season, but it has not yet happened.

Starting in 2012, with the new one-game play-in game for the two wild card teams in determining the #4 seed in playoffs, if two teams tie for a division title and would both be in the playoffs, a one-game playoff would be held because it would determine which team receives the bye in the playoff, and if the winning percentage of the losing team be still enough to be a #1 or #2 wild card, the loser would be the said wild card.

Avoiding any confusion with the term "Playoffs" as the oft-used but unofficial name of MLB's post-season tournament, the term "Tiebreaker" is now MLB's preferred term for a one-game playoff.

History
Through the 2009 MLB season, there have been 13 occasions where a playoff was needed to break a tie in a league, division, or wild card race. Of these playoffs, nine have been one-game playoffs and the other four were three-game playoffs. Prior to the advent of divisional play in 1969, the National League broke ties for its league championship with a three-game playoff. The American League has always used one-game playoffs.

Prior to the wild card playoff system, all five pennant playoffs in the National League had involved the Brooklyn/Los Angeles Dodgers (which won the coin toss for home field all five times, yet lost all except the 1959 one), and both American League playoffs had involved the Boston Red Sox (who hosted both and lost both). None of the one-game playoffs since 1995 have involved those teams.

No playoff needed
Rules state a tiebreaking game was held only to determine who is in or out of the playoffs, not to determine seeding within the playoffs. From 1995 until 2011, the rule applied to the divisions, but starting in 2012, the rule applies only if the two wild cards be tied (winner of the MLB tiebreaking procedure gains home-field advantage).

Since the advent of the wild card in 1995, there have been three occasions on which a tiebreaker was not necessary as the two teams that were tied for a division lead were also atop the wild card standings. In 2001, the Houston Astros and St. Louis Cardinals tied for first in the National League Central with record of 93–69. In 2005, the New York Yankees and Boston Red Sox each finished 95–67 in the American League East. In 2006, the San Diego Padres and Los Angeles Dodgers finished tied with records of 88–74 in the National League West. In all three situations, the team with the better head-to-head record (the 2001 Astros, 2005 Yankees, and 2006 Padres) were declared winners of the division, thus receiving a better seed in the playoffs. The other team (the 2001 Cardinals, 2005 Red Sox, and 2006 Dodgers) entered the playoffs as the wild card.

Starting in 2012, with the play-in game between wild card teams, the rule was eliminated for division titles only because of the bye that goes with the division winner. The rule still applies for wild cards to determine the team that will host the wild card game.

Make-up games
On some occasions a previously postponed game may be made up at the end of the season in order to settle entry into the playoffs. Although such a game is technically a mere regular-season game, it can have the effect and feel of a playoff.

On September 23, 1908, Johnny Evers of the Chicago Cubs capitalized on a base-running mistake by young Fred Merkle of the New York Giants to invalidate a game-ending winning run. As thousands of fans were on the field and darkness was approaching, the game did not immediately resume. As it turned out, the Cubs and Giants ended the season in a tie for the pennant, and the postponed game was replaced by a new game played on October 8, 1908 at the Polo Grounds. The Cubs prevailed 4–2, and advanced to the 1908 World Series.

In 2008, the Chicago White Sox ended the season 1/2 game behind the Minnesota Twins. The fractional difference was due to the September 13 game between the White Sox and the Detroit Tigers, which had been rained out and not yet rescheduled. To determine whether, if the game had not been rained out, there would have been a tie between the Twins and White Sox, the White Sox and Tigers played the make-up game at the end of the season on September 29. The White Sox won, resulting in a Twins-White Sox tie. To break the tie, the White Sox and Twins played a one-game playoff in Chicago (see below). Make-up games were also played after the season's end in 1973 and 1981.

Between 1901 and 1938, during a time when games were more often delayed by darkness and not always made up, there have been at least nine occasions on which making up postponed games might have resulted in a different pennant outcome, but the games were not made up.

National Football League
The National Football League now has an elaborate formula for breaking ties in the qualification for its playoffs. One game playoffs are no longer possible - in the highly unlikely event that two teams tied in all relevant statistical criteria, the rules stipulate that a coin toss settle the tie. However, before the merger of the National Football League and the American Football League in 1970, it was possible to have a playoff game if 2 teams tied for a division title. The NFL had 9 of these playoffs occur between 1941 and 1965. The AFL had 2 playoffs in 1963 and 1968. The All-America Football Conference, which merged with the NFL after the 1949 season (with the NFL absorbing three of the AAFC's franchises - the Cleveland Browns, San Francisco 49ers, and the original Baltimore Colts) also held a playoff tiebreaker game in 1948.

The Chicago Bears and the Portsmouth Spartans of the National Football League tied at the end of the 1932 season. They held an extra game to determine the champion. Unlike subsequent post-season playoffs, this game was considered part of the regular season, as are the baseball tie-breaking playoff games described above.

The great interest generated by the 1932 playoff game led the NFL to split into two divisions in 1933, and began playing a single post-season NFL Championship game. If two teams in a single division tied for first place, the rules also provided for a one-game tie-breaking playoff to determine which team would advance to the league championship game. This was the practice from 1933 to 1966. Unlike the 1932 contest, these tiebreakers were not part of the regular season's standings. The league's last one game playoff occurred in 1965. Since 1967, when it split into 4 divisions, the NFL has used a set of tiebreaking rules to break ties. The AFL did not adopt tiebreakers before the merger.

NFL one game playoffs
Home teams in bold.

* During the time that tie-breaker games were in use, NFL teams were grouped into both "Divisions" (from 1933-1949), and "Conferences" (1950 and later).

AFL one game playoffs
Home team in bold.

AAFC one game playoff
Home team in bold.

* ''Not to be confused with the modern day Buffalo Bills. The modern-day Indianapolis Colts joined the NFL after the AAFC team folded.''

National Basketball Association
In its early years, the National Basketball Association held tie-breaker games at the end of the season, if necessary. The first two games (a three team playoff) were played during the 1947-48 season, the leagues second year in existence, when it was still known as the Basketball Association of America. The second of these, however, was only used to determine the playoff seeding for the Chicago Stags and Baltimore Bullets. In fact, five of the seven one-game playoffs in NBA history were used for seeding purposes, and both teams advanced to the playoffs despite the outcome.

The American Basketball Association, which formed in 1967, did not hold a tie-breaker game in its first season, when the Kentucky Colonels and New Jersey Americans (later known as the New York Nets, New Jersey Nets, and currently as the Brooklyn Nets) tied for fourth place in the Eastern Division with a record of 36-42. A game was scheduled between the two teams in New Jersey, but the Americans' facility was booked and the replacement site picked by the team was in such poor condition that they were forced to forfeit the game by the league office. The Colonels were given the playoff spot despite going just 4-7 against the Americans during the regular season. The next time two teams finished tied for the final playoff spot in a division, the ABA did hold a tie-breaker game. The ABA would later merge with the NBA, with four teams from the ABA joining the NBA: the Denver Nuggets, Indiana Pacers, New York Nets and San Antonio Spurs.

NBA one game playoffs
Home team in bold.

* Not to be confused with the modern day Washington Wizards, who were known as the Baltimore Bullets from 1965 to 1973.

ABA one game playoffs
Home team in bold.

The New Jersey Americans (now the Brooklyn Nets of the NBA) forfeited the playoff game to the Kentucky Colonels when the Commack Arena on Long Island, where the game was scheduled to be played, was deemed unsuitable due to a wet floor from a leaky ice surface.

World Hockey Association
Though the National Hockey League, the only major professional ice hockey league in North America, has never had one-game playoffs in its nearly century long existence, the World Hockey Association, which operated in the 1970s, did. Only one such game was played, a neutral site game played in Calgary after the WHA's first regular season between the Alberta Oilers (now Edmonton Oilers) and the Minnesota Fighting Saints. The WHA would later merge with the NHL, with four WHA franchises switching leagues: the Oilers, the Hartford Whalers (now Carolina Hurricanes), the Quebec Nordiques (now Colorado Avalanche), and the Winnipeg Jets (now Phoenix Coyotes).

Ivy League basketball
In U.S. college basketball, Ivy League rules call for a one-game playoff if two teams are tied for the conference title in both men's and women's basketball, with the winner claiming the conference's automatic bid to the NCAA Tournament. If more than two teams are tied, a series of one-game playoffs is held.

In men's basketball, eight seasons have ended in such a playoff, with the most recent being the 2010–11 season in which Harvard and Princeton finished tied. Before 2011, the last time a playoff was needed was 2001–02, when Yale, Penn, and Princeton ended in the only three-way tie in Ivy men's basketball history. A three-way playoff in women's basketball occurred most recently in the 2007–08 season, in which Cornell, Dartmouth, and Harvard all finished at 11–3 in league play. It was determined that Dartmouth would play Harvard in the first playoff game, with the winner facing Cornell. Dartmouth won the first playoff game, with Cornell winning the playoff final.

Lamar Hunt U. S. Open Cup
When the 2011 Premier Development League qualifiers in a region could not be settled by the four-stage qualifier of points, then wins, then goal difference, and goals scored, for the final position, the two teams, Kitsap Pumas and Portland Timbers U23's, agreed to discard the traditional lottery draw for the final slot and replace it with the result of their next scheduled game in the league also a one-game playoff to determine the final slot in the U. S. Open Cup. If the game ended in a tie, penalty kicks would be used to determine the U. S. Open Cup qualifier, but not for PDL standings.

Use in the Philippines
In the Philippines, the one-game playoff is called a "knockout game". In all instances, all games are held in neutral venues, since the home-and-away system is not used.

Philippine Basketball Association
As opposed to North American usage, in which one-game playoffs are held to determine a champion, in the Philippine Basketball Association (PBA), one-game playoffs are held when teams are tied in a last qualifying seed in the team standings. An extra game will be played in order to determine which team would be eliminated and which team will advance.

With the restructuring of the playoffs starting at the 2005-06 season, one game playoffs are also held which do not merit automatic elimination. When two teams are tied on the last qualifying seed for a stage (such as the #2 seed for the last semifinal berth), a classification game will be played in order to determine which team will clinch the higher seed. If the two teams are not tied on the last qualifying seed (such as the #1 seed where both teams are in the semifinals already), the points difference between the tied teams will be used to determine which team clinches the higher seed. Consequently, one-game playoffs that don't eliminate the loser are called "knockdown games."

Playoffs such as those after the 2004 restructuring are common due to the low amount of games played in the elimination round (14-18). In fact, each conference was able to feature at least one playoff game, until the 2007-08 PBA Philippine Cup where even though there were tied teams, the team's positions aren't critical so they were resolved on the point differential among the tied teams' games.

Curiously, no elimination playoff game has been held right after the elimination round; therefore all games mentioned were for seeding purposes and no teams were eliminated, although losing teams had a tougher road to qualify to the succeeding stages.

College sports
Starting at the reformation of the playoff structure of the UAAP basketball tournament on 1993 (actually first used on 1994 since UST swept the playoffs and were named automatic champions on 1993), where the top 4 teams qualify for the semifinals, with the top 2 teams clinching the twice to beat advantage, a playoff will be held if two teams were tied for the fourth and last semifinal berth.

Lately, when three or more teams are tied, all three teams undergo a series of one-game playoffs to determine the top seed and which team is eliminated.

Men's playoff results include: Ties may also broken when two teams are tied for third, second and first seeds, although the competing teams still qualify for the playoffs when they lose; a playoff game for the #2 seed serves as a de facto game 1 of a best-of-three series.

The UAAP has also used this format for the volleyball tournaments.