The International Tennis Federation (ITF) is the governing body of world tennis, wheelchair tennis, and beach tennis. It was founded in 1913 as the International Lawn Tennis Federation by twelve national tennis associations. As of 2016, there are 211 national and six regional associations that make up the ITF's membership.
The Association of Tennis Professionals (ATP) is the governing body of the men's professional tennis circuits – the ATP Tour, the ATP Challenger Tour and the ATP Champions Tour. It was formed in September 1972 by Donald Dell, Jack Kramer, and Cliff Drysdale to protect the interests of professional tennis players, and Drysdale became the first president. Since 1990 the association has organized the ATP Tour, the worldwide tennis tour for men and linked the title of the tour with the organization's name. It is the governing body of men's professional tennis. In 1990 the organization was called the ATP Tour, which was renamed in 2001 as just ATP and the tour being called ATP Tour. In 2009 the name of the tour was changed again and was known as the ATP World Tour, but changed again to the ATP Tour by 2019. It is an evolution of the tour competitions previously known as Grand Prix tennis tournaments and World Championship Tennis (WCT). The ATP's global headquarters are in London. ATP Americas is based in Ponte Vedra Beach, Florida; ATP Europe is headquartered in Monaco; and ATP International, which covers Africa, Asia and Australasia, is based in Sydney, Australia.
The WTA Finals is the season-ending championship of the WTA Tour. It is the most significant tennis event in the women'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 WTA Tour is a worldwide top-tier tennis tour for women organized by the Women's Tennis Association. The second-tier tour is the WTA 125K series, and third-tier is the ITF Women's World Tennis Tour. The men's equivalent is the ATP Tour.
The ATP Tour is the sole worldwide top-tier tennis tour for men organized by the Association of Tennis Professionals founded in 1990 that replaced the earlier dual Grand Prix Circuit and WCT Circuit. The second-tier tour is the ATP Challenger Tour and the third-tier is the ITF Men's World Tennis Tour. The equivalent women's organisation is the WTA Tour.
The WTA rankings are the ratings defined by the Women's Tennis Association, introduced in November 1975. The computer that calculates the ranking is nicknamed "Medusa".
The PIF ATP Rankings are the merit-based method used by the Association of Tennis Professionals (ATP) for determining the qualification for entry as well as the seeding of players in all singles and doubles tournaments. The first rankings for singles were published on 23 August 1973 while the doubles players were ranked for the first time on 1 March 1976. Ranking points are awarded according to the stage of tournament reached, and the prestige of the tournament, with the four Grand Slam tournaments awarding the most points. The rankings are updated every Monday, and points are dropped 52 weeks after being awarded. Jannik Sinner is the current men's singles world No. 1.
The WTA Tour is the elite tour for women's professional tennis organized by the Women's Tennis Association (WTA). The 2011 WTA Tour includes the Grand Slam tournaments, the WTA Premier tournaments, the WTA International tournaments, the Fed Cup, the Commonwealth Bank Tournament of Champions and the WTA Championships.
The 2013 ATP World Tour was the global elite professional tennis circuit organized by the Association of Tennis Professionals (ATP) for the 2013 tennis season. The 2013 ATP World Tour calendar comprises the Grand Slam tournaments, the ATP World Tour Masters 1000, the ATP World Tour 500 series, the ATP World Tour 250 series, the Davis Cup and the ATP World Tour Finals. Also included in the 2013 calendar is the Hopman Cup, which was organized by the ITF and does not distribute ranking points.
The 2014 ATP World Tour was the global elite men's professional tennis circuit organized by the Association of Tennis Professionals (ATP) for the 2014 tennis season. The 2014 ATP World Tour calendar comprises the Grand Slam tournaments, the ATP World Tour Masters 1000, the ATP World Tour 500 series, the ATP World Tour 250 series, the Davis Cup and the ATP World Tour Finals. Also included in the 2014 calendar is the Hopman Cup, which is organized by the ITF and does not distribute ranking points.
The 2014 WTA Tour was the elite professional tennis circuit organized by the Women's Tennis Association (WTA) for the 2014 tennis season. The 2014 WTA Tour calendar comprises the Grand Slam tournaments, the WTA Premier tournaments, the WTA International tournaments, the Fed Cup, and the year-end championships. Also included in the 2014 calendar is the Hopman Cup, which was organized by the ITF and did not distribute ranking points.
The 2015 WTA Tour was the elite professional tennis circuit organised by the Women's Tennis Association (WTA) for the 2015 tennis season. The 2015 WTA Tour calendar comprises the Grand Slam tournaments (supervised by the International Tennis Federation, the WTA Premier tournaments, the WTA International tournaments, the Fed Cup, and the year-end championships. Also included in the 2015 calendar is the Hopman Cup, which is organized by the ITF and does not distribute ranking points.
The 2020 WTA Tour was the elite professional tennis circuit organised by the Women's Tennis Association (WTA) for the 2020 tennis season. The 2020 WTA Tour calendar originally comprised the Grand Slam tournaments supervised by the International Tennis Federation (ITF), the WTA Premier tournaments, the WTA International tournaments, the Fed Cup, and the year-end championships.
The 2022 WTA Tour was the global elite women's professional tennis circuit organized by the Women's Tennis Association (WTA) for the 2022 tennis season. The 2022 WTA Tour calendar comprised the Grand Slam tournaments, the WTA 1000 tournaments, the WTA 500 tournaments, the WTA 250 tournaments, the Billie Jean King Cup, and the year-end championships.
The WTA 125 tournaments are the secondary professional tennis circuit organised by the Women's Tennis Association. The 2022 calendar consists of twenty-four tournaments.
The 2023 WTA Tour was the global elite women's professional tennis circuit organized by the Women's Tennis Association (WTA) for the 2023 tennis season. The 2023 WTA Tour calendar comprised the Grand Slam tournaments, the WTA 1000 tournaments, the WTA 500 tournaments, the WTA 250 tournaments, the Billie Jean King Cup, the year-end championships, and the team events United Cup and Hopman Cup. 2023 also marked the return of the WTA to China, after strict COVID-19 protocols in the country and the disappearance of former tennis player Peng Shuai.
The 2023 ATP Tour was the global elite men's professional tennis circuit organised by the Association of Tennis Professionals (ATP) for the 2023 tennis season. The 2023 ATP Tour calendar comprised the Grand Slam tournaments, supervised by the International Tennis Federation (ITF), the ATP Finals, the ATP Tour Masters 1000, the United Cup, the ATP 500 series, the ATP 250 series. Also included in the 2023 calendar were the Davis Cup, Next Gen ATP Finals, Laver Cup, Hopman Cup, none of which distributed ranking points. 2023 marked the return of the ATP tournaments in China after strict COVID-19 protocols in the country.
The 2024 WTA Tour is the global elite women's professional tennis circuit organized by the Women's Tennis Association (WTA) for the 2024 tennis season. The 2024 WTA Tour calendar comprises the Grand Slam tournaments, the WTA 1000 tournaments, the WTA 500 tournaments, the WTA 250 tournaments, the Billie Jean King Cup, the year-end championships, the team events United Cup and the Summer Olympic Games.
The 2024 ATP Tour is the global elite men's professional tennis circuit organized by the Association of Tennis Professionals (ATP) for the 2024 tennis season. The 2024 ATP Tour calendar comprises the Grand Slam tournaments, supervised by the International Tennis Federation (ITF), the ATP Finals, the ATP Masters 1000, the United Cup, the ATP 500 series and the ATP 250 series. Also included in the 2024 calendar are the Davis Cup, the Summer Olympics in Paris, Next Gen ATP Finals and Laver Cup, none of which distribute ranking points.
Jannik Sinner (ITA)
Novak Djokovic (SRB)
Carlos Alcaraz (ESP)
Alexander Zverev (GER)
Daniil Medvedev 
Alex de Minaur (AUS)
Hubert Hurkacz (POL)
Casper Ruud (NOR)
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Grigor Dimitrov (BUL)
Taylor Fritz (USA)
Stefanos Tsitsipas (GRE)
Ugo Humbert (FRA)
Holger Rune (DEN)
Sebastián Báez (ARG)
Félix Auger-Aliassime (CAN)
Alejandro Tabilo (CHI)
