Who is the greatest tennis player of all time?

Serena Williams has dominated more than any other player

Question: Who is the greatest tennis player of all time?
Position‹5 of 5: Serena Williams
Argument1 of 2›: Serena Williams has dominated more than any other player

Serena Williams has won everything there is to win, and done so in dominant fashion.

The argument

Serena Williams's record of victories is the most impressive in the history of tennis. Williams has won 23 Grand Slam singles titles, more than any other player in the Open Era, male or female. As of 2019, she has won every Grand Slam tournament in singles at least three times and in doubles at least twice, the year-end championships five times, and four Olympic gold medals, an all-time record for a tennis player. Twice, she has held all four Grand Slam tournament titles at the same time, and she has won more top-tier WTA tournaments than any other player. Williams has won more prize money than any other female player, winning over double the amount of the second-place player on the all-time money list.

Premises

[P1]Serena Williams has won 23 Grand Slam singles titles, more than any other player in the Open Era. [P2] She holds an all-time record of four Olympic golds, has twice held all four Slam titles at once, and has won more top-tier WTA tournaments and prize money than any other female player. [P3] No other player has dominated the sport so completely across singles, doubles and the Olympics. [C] Therefore, because she has dominated more than any other player, Serena Williams is the greatest tennis player of all time.

Counter-arguments

Advocates for the other players reply that dominance is measured against one's era and rivals, not by a single tally. The sibling cases for Federer, Nadal and Djokovic note that the men's field is far deeper, and Djokovic has since passed 23 majors; Steffi Graf's Golden Slam and Margaret Court's 24 major titles (spanning the amateur and Open eras) complicate the "most impressive record in history" claim. Cross-era and cross-gender comparison is fraught, so an accumulation of titles, however remarkable, does not by itself settle "greatest of all time" over players whose peaks, longevity and level of competition are assessed on different scales.

Rejecting the premises

[Rejecting P1] The 23-Slam figure has since been surpassed on the men's side by Djokovic, and Margaret Court's 24 majors complicates the "more than any other player" claim once eras are included. [Rejecting P2] Records of Olympic golds and simultaneous Slams are remarkable, but the sibling positions argue the men's era offered deeper competition, so raw totals do not straightforwardly rank players across different fields. [Rejecting C] "Greatest of all time" requires weighing era strength, longevity and level of rivalry, which cross-era and cross-gender comparison cannot reduce to a title count — so dominance by tally does not settle the question over Federer, Nadal, Djokovic or Laver.