ATP rankings

The ATP began as the men's trade union in 1972, through the combined efforts of Jack Kramer, Cliff Drysdale, and Donald Dell, and rose to prominence when 81 of its members boycotted the 1973 Wimbledon Championships.

[5] While virtually all ATP members were in favor of objectifying event participation, the system's first No.

1, Ilie Năstase, lamented that "everyone had a number hanging over them", fostering a more competitive and less collegial atmosphere among the players.

[6] The original ATP ranking criteria, which were then regularly published weekly only from mid-1979 and persisted through the 1980s, were based on averaging each player's results, though the details were revised a number of times.

[4][5] Starting in 1990, in conjunction with the expansion of ATP purview as the new men's tour operator, the ranking criteria were replaced with a 'best of' system modeled after competitive downhill skiing.

[9] A player who is out of competition for 30 or more days, due to a verified injury, will not receive any penalty.

The ATP Finals will count as an additional 20th tournament in the ranking of its eight qualifiers at season's end.

[2] Players with multiple consecutive withdrawals who are out of competition for 30 days or longer because of injury are not subject to a ranking penalty as long as verified and approved medical forms are provided; or, a player will not have the ranking penalty imposed if he completes the Promotional Activities requirement as specified under "Repeal of Withdrawal Fines and/or Penalties" or if the on-site withdrawal procedures apply.

1 in their disciplines, and the top-eight players and teams participate in the season-ending championship, the ATP Finals.

[20] Starting in 2016, points were no longer awarded for Davis Cup ties,[21] nor for the tennis tournament at the Summer Olympics.