Naomi Osaka defeated Serena Williams in the final, 6–2, 6–4 to win the women's singles tennis title at the 2018 US Open. It was her first major title. Osaka became the first Japanese to win a major singles title.[1][2] With the win, she made her top-10 rankings debut. Williams was attempting to equal Margaret Court's all-time record of 24 major singles titles, and to set a new Open Era record by winning a seventh US Open singles title.
Simona Halep's first-round loss to Kaia Kanepi marked the first time in the Open Era that the top seed lost in the first round.[3] The losses of Halep in the first round and second seed Caroline Wozniacki in the second round marked the first time that the top two seeds failed to reach the third round, and the second time this happened at any major in the Open Era (following the 2014 French Open).
Kathinka von Diechmann became the first player from Liechtenstein to qualify for the main draw of a major for the first time.
This marked the final major appearance for former world No. 2 and 2015 WTA Finals champion Agnieszka Radwańska, who lost in the first round to Tatjana Maria. This also marked the first main-draw US Open appearance for future two-time champion Aryna Sabalenka, who reached the fourth round and was the only player in the tournament to win a set against Osaka.