The ATP Rankings, as defined by the Association of Tennis Professionals (ATP), are the "objective merit-based method used for determining qualification for entry and seeding in all tournaments for both singles and doubles, except as modified for the ARAG ATP World Tour Team Championship and Barclays ATP World Tour Finals (singles or doubles)." The rankings period is "the immediate past 52 weeks, except for: Barclays ATP World Tour Finals, singles and doubles, which is dropped on the Monday following the last ATP World Tour event of the following year; Futures Series tournaments that are only entered into the system on the second Monday following the tournament's week. Once entered, all tournaments, except for the Barclays ATP World Tour Finals, remain in the system for 52 consecutive weeks."

A player's ATP Ranking is based on the total points he accrued in the following 19 tournaments (18 if he did not qualify for the Barclays ATP World Tour Finals):

The requirement to play in four ATP World Tour 500 events does not apply to a player who was outside the top 30 in the previous year-end ranking; however, no more than four of his results from 500 level events may be counted. For a better result within the same tour type to be transposed one has to wait for the expirement of the first worse result from previous year. It only expires at the drop date of that tournament and only if the player reached a worse result or hasn't entered the current year.

Novak Djokovic (Serbian: Новак Ђоковић or Novak Đoković; pronounced [nɔ̂ʋaːk dʑɔ̂ːkɔʋitɕ] ( listen); born 22 May 1987) is a Serbian professional tennis player who has been ranked World No. 1 by the Association of Tennis Professionals (ATP) since 4 July 2011. He has won five Grand Slam singles titles: the 2008, 2011 and 2012 Australian Open, the 2011 Wimbledon Championships, and the 2011 US Open. By winning three Majors in 2011, Djokovic became the sixth male player in the open era to win three Majors in a calendar year.

He is the first male player representing Serbia to win a Major singles title and the youngest player in the open era to have reached the semifinals of all four Grand Slam events, separately and consecutively. Amongst other titles, he won the Tennis Masters Cup in 2008 and was on the team which won the 2010 Davis Cup. He also won the bronze medal in singles at the Beijing Olympics in 2008. He has won 11 Masters 1000 series titles placing him joint fourth on the all time list. Djokovic has quickly moved up in the rankings of history. Tennis Channel ranked him number 40 , and former player Pat Cash said he is one of the greatest ever.

Victoria Azarenka (Belarusian: Вікторыя Фёдараўна Азаранка, Russian: Виктория Фёдоровна Азаренко; born 31 July 1989) is a Belarusian professional tennis player. She is the current World No. 1 as of 28 May 2012.

She won the 2012 Australian Open singles title, becoming the first Belarusian player to win a Grand Slam in singles. Her other achievements include winning two mixed doubles Grand Slam titles, the 2007 US Open with Max Mirnyi and the 2008 French Open with Bob Bryan.

At age 16, Azarenka moved to Scottsdale, Arizona from Minsk, Belarus, to train. In this she was aided by National Hockey League goalie Nikolai Khabibulin and his wife, who is a friend of Azarenka's mother. In 2010 she briefly considered a break from the sport of tennis to focus on education, however, after a conversation with her grandmother she decided to continue playing. It is the inspiration from her grandmother that is regarded as the key for her continued developments in the sport. Azarenka is romantically involved with tennis player Sergei Bubka Jr, son of former Olympic gold medalist and World Champion, Sergey Bubka.

Rafael "Rafa" Nadal Parera (Catalan: [rəˈfɛɫ nəˈðaɫ pəˈɾeɾə]; Spanish: [rafaˈel naˈðal paˈɾeɾa]) (born 3 June 1986) is a Spanish professional tennis player and a former World No. 1. As of 28 May 2012 (2012 -05-28)^[update], he is ranked No. 2 by the Association of Tennis Professionals (ATP). He is widely regarded as one of the greatest players of all time; his success on clay has earned him the nickname "The King of Clay", and has prompted many experts to regard him as the greatest clay court player of all time.

Nadal has won ten Grand Slam singles titles, including a record six French Open titles (tied with Bjorn Borg), the 2008 Olympic gold medal in singles, a record 21 ATP World Tour Masters 1000 tournaments, and also was part of the Spain Davis Cup team that won the finals in 2004, 2008, 2009 and 2011. He completed the Career Grand Slam by winning the 2010 US Open, being the seventh player in history, and the youngest in the open era, to achieve it. He is the second male player to complete the Career Golden Slam (winner of the four grand slams and the Olympic Gold medal) after only Andre Agassi.