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At No.97. Sloane Stephens was the youngest player in year‐end Top 100 in 2011; and after a phenomenal sophomore season, reached No.38 and was the only teenager in the year‐end Top 50 in 2012. At No.12 she was the youngest player in year‐end Top 20 in 2013 when she advanced to quarterfinals at Wimbledon (l. eventual champion Bartoli) and to the semifinals at Australian Open (d. S.Williams in QF, l. eventual champion Azarenka).
In 2015 Stephens won her first WTA singles title, it Washington, DC (d. Pavlyuchenkova in F). That was her 84th main draw event; at No.35, she had been the highest‐ranked player yet to reach a WTA final.
Stephens ended 2016 ranked No.36 (her fifth consecutive Top 40 finish) clinching three WTA singles titles in Auckland (d. Goerges in F), Acapulco (d. Cibulkova in F) and Charleston (d. Vesnina in F).
In 2017, after an 11 months injury lay-off, Stephens registered first four wins of 2017 in Toronto to reach to reach the semifinal (as WC, l. Wozniacki); subsequently, she jumped 783 spots on WTA rankings. Then, she backed up that result with another semifinal run at Cincinnati (as WC, l. Halep) and returned to Top 100 of rankings as a result. At US Open, Stephens capped a historic summer comeback by upsetting Cibulkova, V.Williams and Keys to become the fifth unseeded woman (ranked No.83) in the Open Era to win a major. Then, she didn't win another singles match. She lost both her round robin clashes in Zhuhai and in the Fed Cup final, though the United States managed to beat 3he Belarus.
In 2018, Stephens ended the season losing the WTA Finals title-match in Singapore. Stephens’ record in tour-level finals stands at 6-3. 2018 marked the first season she has reached four finals in a year. Before her defeat to Svitolina in the season-ending match, she had won one title, in Miami (d. Ostapenko in F), making consequently her Top 10 debut: she then went on to post a career-high ranking of No.3 over the summer (July 16, 2018). In Miami, she helped make history as the USA provided the winners in all four events (Stephens, Vandeweghe w/Barty, Isner, and Bryan brothers).
Stephens reached the second Grand Slam final of career, finishing runner-up at Roland Garros, and contested the title-match at Montréal losing to World No.1 Halep both times. After her last loss to Halep, her record against reigning No.1s slipped to 0-8, losing to Wozniacki (2011 Indian Wells), Azarenka (2013 Australian Open), S.Williams (2013 US Open, 2015 Indian Wells, 2015 Madrid, 2015 Roland Garros) and Halep (2018 Roland Garros and 2018 Montreal).
In Grand Slam play, aside from Roland Garros, she fell at the first round at Australian Open (l. Zhang) and Wimbledon (l. Vekic) and made the quarterfinals at US Open (as defending champion, l. Sevastova). In other tournaments, she enjoyed a quarterfinal run in Acapulco (d. Parmentier and Rus, l. eventual R-Up Voegele) and posted round 16 exits in Indian Wells (l. eventual R-Up Kasatkina), Madrid (l. Pliskova), Rome (l. Garcia), Cincinnati (l. Mertens) and Beijing (l. Cibulkova).
Entering the WTA Finals, she owned the least amount of wins across the season to qualify (33 at beginning of Singapore). However, she became the tenth player to reach the final on her first appearance. Stephens, the first American woman not named Williams into the final there since 2001 when Davenport withdrew prior to the match versus Serena Williams, posted a perfect 3-0 record in the round robin stage this week, the 21st occasion this has happened, defeating No.4 Osaka, No.2 Kerber and No.9 Bertens in the round robin stage, before dispatching No.8 Karolina Pliskova in the semifinals. She ended the season with a 5-2 record against Top 5 player and an 8-5 mark versus Top 10 opponents.