WTA: Women's Tennis Association
The Women’s Tennis Association (WTA) is the world’s biggest organisation for female professional tennis players, and it can therefore be viewed as the female equivalent of the Association of Tennis Professionals (ATP) for male players. It was founded in 1973 by Billie Jean King, who was one of the most successful female players around at that time. King, as well as eight other players, made up the nine original members of the Association.
Almost half a century has gone by since the WTA was founded, and today there are over 2,500 members from all around the world, including such household names as Ashleigh Barty, Simona Halep, Sofia Kenin and Serena Williams.
From 1990 until 2008, WTA tournaments were organised into five different tiers, with Tier I being for the most elite events, Tier II for second-level tournaments, and so on. This structure changed in 2009 when the tier system was replaced by Premier Tournaments and International Tournaments. The Premier Tournaments include four Premier Mandatory tournaments (the BNP Paribas Open, Miami Open, Mutua Madrid Open and China Open), five Premier 5 tournaments and twelve Premier tournaments.
Although the WTA is not involved in the running of the four Grand Slam tournaments that pepper the annual tennis calendar (the Australian Open, the French Open, Wimbledon and the US Open), the most talented of its members obviously participate in them and their performance in Grand Slams is therefore included in the WTA Rankings system.
The WTA Rankings system has been running since 1975, and Chris Evert was the first player to be named the WTA world number one. Evert spent a total of 260 weeks in the number one position, and only two players have bettered that record, with Serena Williams, Martina Navratilova and Steffi Graf holding the number one position for 319, 332 and 377 weeks, respectively.