Naomi Osaka was the defending champion,[4] but was defeated by Fernandez in the third round.
The final marked the first all-teenage major final since Serena Williams defeated Martina Hingis in 1999, and the first women's singles major final in the Open Era to feature two unseeded players.[5] Raducanu and Fernandez both made their top 30 debuts following the tournament. Fernandez was the youngest player to defeat three top-five seeded players in the same major since Williams at the 1999 US Open.[6][7]
None of the top 20 seeds lost prior to the third round, the first time this occurred since the introduction of the 32-seed format in 2001.[10] The defeats of Karolína Plíšková and Barbora Krejčíková in the quarterfinals guaranteed two first-time major finalists; Raducanu and Fernandez emerged to become those players. This also ensured that, for the first time since 2014, eight different players contested the four major finals in a season.
The following are the seeded players. Seedings are based on WTA rankings as of August 23, 2021. Rank and points before are as of August 30, 2021.
As a result of pandemic-related adjustments to the ranking system, players are defending the greater of their points from the 2019 and 2020 tournaments.[11] In addition, points from tournaments held during the weeks of September 9, 2019 and September 7, 2020 will be dropped at the end of the tournament and replaced by the player's next best result.