2021 US Open – Women's singles

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. It was her first major title. Raducanu became the first qualifier to win a major. She was 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 tournament debut (after Bianca Andreescu in 2019). Aged 18, Raducanu was the youngest major champion since Maria Sharapova at the 2004 Wimbledon Championships, and with a ranking of world No. 150, the lowest-ranked player to win a major since Kim Clijsters at the 2009 US Open. She did not lose a set during the tournament, including during her three qualification matches, and was not taken to a tiebreak in any set. It was her first WTA Tour-level singles title, making her the fourth woman in the Open Era to win a major as her first singles title. Raducanu won the title on only her second major main-draw appearance, an Open Era record. Naomi Osaka was the defending champion, but was defeated by Fernandez in the third round. 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. 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. She was the first player of Southeast Asian descent (Filipino) to reach the final. This was the first major since the 2011 French Open and first US Open since 2003 where neither of the Williams sisters participated. 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. 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. This marked the final US Open appearance of 2016 champion and former world No. 1 Angelique Kerber; she lost to Fernandez in the fourth round. Kerber subsequently went on maternity leave in 2023 and retired from professional tennis in 2024.