Emma Raducanu defeated Leylah Fernandez in the final, 6–4, 6–3 to win the women's singles tennis title at the 2021 US Open. She became the first qualifier, male or female, to reach a major final and win a major title, as well as the first singles qualifier to reach the semifinals at the US Open. Additionally, she became the first British woman to win a singles major since Virginia Wade at the 1977 Wimbledon Championships and the second player to win the US Open on her debut appearance, following Bianca Andreescu in 2019.[1][2][3] Aged 18, she also became the youngest major champion since Maria Sharapova at the 2004 Wimbledon Championships and with a WTA Ranking of world No. 150, the lowest-ranked player to win a major since Kim Clijsters at the 2009 US Open. Raducanu won the title without losing a set during the tournament, including during her three qualification matches. Furthermore, she did not play a tiebreak in any set. This was her first WTA singles title, making her the fourth woman in the Open Era to win a major tournament as their maiden singles title.
The final marked the first all-teenage major final since Serena Williams defeated Martina Hingis at the 1999 US Open and the first women's singles major final in the Open Era to feature two unseeded players.[4] Raducanu and Fernandez both made their top 30 debuts following the tournament. Fernandez was the youngest player to defeat three top 5 seeded players in the same major since Williams at the 1999 US Open.[5][6]
Naomi Osaka was the defending champion,[7] but she lost to Fernandez in the third round.
None of the top 20 seeds lost prior to the third round of the tournament, marking the first time this had 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 Grand Slam 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.
^Kirsten Flipkens was the next player initially entered into the main draw, but she later withdrew due to an ongoing left ankle injury.[17] After Flipkens's withdrawal from the event, Venus Williams was the next player initially entered into the main draw, but she also withdrew due to a leg injury.[14]
Bold denotes the mandatory tournaments (WTA 1000) – Tournaments are affected by the COVID-19 pandemic * – Tournaments are introduced due to the impact of the COVID-19 pandemic