No.1 seed Naomi Osaka has played Katerina Siniakova once before, in the first round of Doha last year. The Japanese player won that match 6-4, 6-0. Siniakova owns four career Top 10 wins, including over Simona Halep in the second round of Shenzhen in 2017 and Caroline Wozniacki in the 2017 Bastad final, but an upset of Osaka would be her first Top 3 win.
Defending champion Simona Halep has lost just one set to No.27 seed Lesia Tsurenko in seven previous meetings since their first encounter in a 2009 ITF W25 tournament in Opole. That was in their second-round match at Wimbledon 2014, their fourth match, which the Romanian won 6-3, 4-6, 6-4. Halep has already defeated the Ukrainian twice in 2019 – 6-2, 6-3 in the second round of Doha in February and 6-3, 7-5 in the third round of Dubai the following week.
A first-time Grand Slam quarterfinalist is guaranteed from the section of the draw vacated by Petra Kvitova, who withdrew with an arm injury before playing her first-round match; the contenders are Amanda Anisimova, Irina-Camelia Begu, Ekaterina Alexandrova and Aliona Bolsova. Anisimova and Begu, who play each other, have both reached the fourth round of a major before, the American at the Australian Open in January and the Romanian at the 2015 Australian Open and Roland Garros 2016, while Alexandrova and Bolsova are playing the third round of a major for the first time (indeed, this tournament is Bolsova’s Grand Slam main draw debut). Both match-ups are first-time encounters.
Four former Roland Garros semifinalists remain in the top half of the draw: three-time champion Serena Williams, who has reached the last four here on five occasions (2002-03 and 2013-15); defending champion Simona Halep, who also reached the 2014 and 2017 finals; 2014 semifinalist Andrea Petkovic and 2018 semifinalist Madison Keys.
Amanda Anisimova is the only 2019 red clay titlist remaining in the top half of the draw (joining Istanbul winner Petra Martic in the bottom half): the American won her maiden trophy in Bogota in April. In addition, Madison Keys won Charleston on green clay in April.