won her first Grand Slam title, defeating Madison Keys in the final, 6–3, 6–0, to win the Women's Singles tennis title at the 2017 US Open. It was the first all-American women's final at the US Open since 2002, and the second time in three years that the final featured two first-time Grand Slam singles finalists from the same country. Stephens became the second unseeded woman in the Open Era to win the US Open after Kim Clijsters in 2009. Stephens and Keys became the first Americans to reach the US Open singles final other than the Williams sisters since Lindsay Davenport in 2000 and any Grand Slam final since Davenport at the 2005 Wimbledon Championships. Angelique Kerber was the defending champion, but was defeated in the first round by Naomi Osaka. Kerber became the second US Open defending champion to lose in the first round after Svetlana Kuznetsova in 2005. For the first time since 1981 at the US Open—and at any Grand Slam event since the 1985Wimbledon Championships—all four semifinalists were American. Both occasions were also the last time that four players from the same country accomplished these feats. In addition, Kaia Kanepi became the first qualifier to reach the US Open quarterfinals since Barbara Gerken, also in 1981. This was Maria Sharapova's first Grand Slam appearance since the 2016 Australian Open, following a suspension for violating the anti-doping rules. Sharapova was unseeded in Grand Slam for the first time since the 2009 French Open, was awarded a wildcard into the main draw and advanced to the fourth round, where she lost to Anastasija Sevastova. Garbiñe Muguruza became the new WTA No. 1 player at the end of the tournament despite losing in the fourth round, after Karolína Plíšková failed to defend her finalist points from 2016. Eight of the top nine seeds were in contention for the no. 1 ranking at the start of the tournament. Venus Williams became the first player in history to reach the semifinals of the US Open 10 years apart and then do so another 10 years apart.
