ATP Finals

The ATP Finals is the season-ending championship of the ATP Tour. It is the most significant tennis event in the men's annual calendar after the four majors, as it features the top eight singles players and top eight doubles teams based on their results throughout the season. The eighth spot is reserved, if needed, for a player or team who won a major in the current year and is ranked from ninth to twentieth.

The tournament uses a unique format not seen in other ATP Tour events, where the singles players and doubles teams are separated into two groups of four, within which they each play three round-robin matches. After the round-robin stage, the top two performers from each group play in knock-out semifinals and a final to determine the champion(s).

The tournament was first held in 1970, shortly after the beginning of the Open Era. Novak Djokovic holds the record for the most singles titles with seven, while Peter Fleming and John McEnroe jointly hold the record for the most doubles titles with seven (all won consecutively as a team).

In the tournament's current format, the champion can earn a maximum of 1,500 ranking points, if they win the event after going undefeated in the round-robin stage. By winning the 2022 title, Djokovic earned a record $4,740,300, the highest payout for a tournament winner in tennis. Also that year, Rajeev Ram and Joe Salisbury claimed $930,300, the highest payout in doubles history.

History
The ATP Finals is the fifth iteration of a championship which began in 1970. It was originally known as the Masters Grand Prix and was part of the Grand Prix tennis circuit. It was organised by the International Lawn Tennis Federation (ILTF) and ran alongside the competing WCT Finals from 1971 to 1989. The Masters was a year-end showpiece event between the best players on the men's tour, but did not count for any world ranking points.

In 1990, the Association of Tennis Professionals (ATP) took over the running of the men's tour and replaced the Masters with the "ATP Tour World Championships". World ranking points were now at stake, with an undefeated champion earning the same number of points they would earn for winning one of the four Grand Slam events. The ITF, who continued to run the Grand Slam tournaments, created a rival year-end event known as the Grand Slam Cup, which was contested by the 16 players with the best records in the Grand Slam tournaments of the season (1990–99).

In December 1999, the ATP and ITF agreed to discontinue the two separate events and create a new jointly-owned event called the "Tennis Masters Cup". As with the Masters Grand Prix and the ATP Tour World Championships, the Tennis Masters Cup was contested by eight players and teams. However, the player or team ranked number eight in the ATP Race world rankings was not guaranteed a spot: if a player or team won one of the year's majors and finished the year ranked from ninth to twentieth, they were included in the Tennis Masters Cup instead. If two outside the top eight won majors, the higher-ranked of the two in the world rankings took the final spot. This accommodation for major champions continues in the event's current form.

In 2009, the championship was renamed the "ATP World Tour Finals" and was held at The O2 Arena in London. The contract ran through 2013, but was extended multiple times until it was last held there in 2020. In 2017 the event was renamed the "ATP Finals." In April 2019, the ATP announced that Turin would host the ATP Finals from 2021 to 2025. For most of its history, the event has been considered the most important indoor tennis tournament in the world (there were a few exceptions when the event was held outdoors: 1974 in Melbourne & 2003–04 in Houston). The indoor atmosphere allows for controlled conditions of play, both in terms of the court surface and the court's illumination.

In recent years it has been played on indoor hard courts, however, indoor carpet was used in some previous editions. On one occasion, when Melbourne hosted the event in 1974, the grass courts of Kooyong Stadium were used; the tournament was staged only 1–2 weeks before the 1975 Australian Open, which was also played on grass. Apart from 1974, all tournaments have been on a hard court variant, which has prompted calls from some players (such as Rafael Nadal) to feature a greater variety of surfaces, including clay courts.

For many years, the doubles event was held as a separate tournament staged the week after the singles competition, but more recently both events have been held together during the same week and in the same venue.

In 2020, amid the COVID-19 pandemic and in an effort to reduce the number of staff on-site, the ATP introduced live electronic line-calling powered by Hawk-Eye Live. Instead of line umpires, the system detects the relevant movements of the player and where the ball bounces on court. A pre-recorded voice announces "Out", "Fault", and "Foot fault". Also, video review was also introduced for suspected double bounces, touches, and other reviewable calls.

The tournament has traditionally been sponsored by the title sponsor of the tour; however, in 1990–2008 the competition was not sponsored, even though the singles portion of the event, as part of the ATP Tour, was sponsored by IBM. In 2009, the tournament gained Barclays PLC as its title sponsor. Barclays confirmed in 2015 that they would not renew their sponsorship deal once it expires in 2016. On 25 May 2017, it was announced that Nitto Denko would be the main sponsor for the tournament through 2020. In September 2020, Nitto Denko announced it will extend its title partnership of the ATP Finals for another five years, until 2025.

Qualification
The criteria to qualify for the ATP Finals are as follows:


 * 1) Players and teams who finish the season ranked in the top seven in the ATP race automatically qualify.
 * 2) The eighth spot is reserved for a player or team who won a major in the season and is ranked from eighth to twentieth. Goran Ivanišević in 2001, Albert Costa in 2002, Gastón Gaudio in 2004, and Marin Čilić in 2014 are the singles players who have qualified due to their major title despite not ending in the top eight in the ATP race.
 * 3) If more than one player or team won a Grand Slam event in the season and are ranked from eighth to twentieth, then whoever is highest-ranked is awarded the eighth spot; whoever is second highest-ranked is made first alternate.
 * 4) If there is no player who won a major in the season and is ranked from eighth to twentieth, then the eight spot is awarded to the player ranked eighth.

Two alternates also attend the ATP Finals. If the first alternate has already been selected according to (3) mentioned above, then the second alternate is the highest-ranked player who has not otherwise qualified for the event. If both alternate spots are available, they are awarded to the two highest-ranked players who did not otherwise qualify for the event.

An alternate can replace a player who withdraws before the round-robin stage is over, so long as the player who withdraws still has at least one round-robin match left to play. When an alternate enters the competition, his results are considered separately, i.e. the alternate does not inherit the results of the player he is replacing. If an alternate's round-robin results qualify him for the semifinals, then he may continue into the single-elimination rounds.

Format
Unlike other events on the ATP Tour, the ATP Finals is not a straightforward single-elimination tournament. The eight players and teams are divided into two groups of four and each play three round-robin matches against the others in their group. After the round-robin stage, the top two performers in each group advance to the semifinals in a knock-out stage. The two winners of the semifinals play a final to determine the champion. In this format, it is theoretically possible to advance to the semifinals with two round-robin losses, but no player in the history of the singles tournament has won the title after losing more than one round-robin match.

To create the groups, the eight players and teams are seeded according to rank. The first and second seeds are placed in Group A and Group B, respectively. The remaining seeds are drawn in pairs (third and fourth, fifth and sixth, seventh and eighth); the first of the pair to be drawn goes to Group A and the other to Group B, and so on.

The format described above has been in place for all editions of the tournament except the following years:
 * 1970–71: All round robin (no groups), no semifinals or finals, the winner was decided based on round-robin standings.
 * 1982–84: 12-player three-round single-elimination tournament (no round robin), the top four seeds received byes in the first round.
 * 1985: 16-player four-round single-elimination tournament (no round robin), no byes.

Group standings
Since 2019, the group standings at the end of the round-robin stage are determined by, in order:
 * Most matches won.
 * Most matches played (for example: the record 1–2 beats 1–1, and 2–1 beats 2–0).

If some players are tied, the following tiebreakers are used depending on how many players are tied (two or three):

If two players are tied, then:
 * Head-to-head round-robin result.

If three players are tied, then the following tiebreakers are used, in order, until all three players are no longer tied OR until only two players are tied, at which point the two-player tie is broken by the head-to-head round robin result:
 * Highest % of sets won.
 * Highest % of games won.
 * Highest ranking at the start of the tournament.

When calculating tiebreakers, a match that ended in a retirement is counted as a 0–2 sets loss for the retiring player and a 2–0 sets win for their opponent, regardless of the actual score when the retirement occurred. When calculating the "Highest % of games won" tiebreaker, a match that ended in a retirement is disregarded.

Singles venues
ATP Finals is the men's premier indoor event of the season, only in three editions it was played outdoors; 1974, 2003 and 2004.

Prize money, ranking points and trophies
The 2023 ATP Finals rewarded the following points and prize money, per victory (Doubles' prize money is per team):
 * An undefeated champion would earn the maximum 1,500 points, and $4,801,500 in singles or $943,650 in doubles.

Additional prizes include the ATP Finals trophy and the ATP year-end No. 1 trophy, all made by London-based silversmiths Thomas Lyte.

List of champions
{|
 * Current through 2023 ATP Finals (active players in bold).
 * -style="vertical-align:top"

Doubles

 * }

Records and statistics

 * Current through 2023 ATP Finals (active players in bold).

Double crown

 * Winning the year-end championships in both singles and doubles in the same year.

Year-end championships triple

 * ATP YEC (active); played since 1970.
 * WCT YEC (defunct); played from 1971 to 1989.
 * ITF YEC (defunct); played from 1990 to 1999.

Doubles
Note: Titles, won by a team of players from same country, count as one title, not two.