Third-seeded Sofia Kenin of the U.S. fell in straight sets to Estonia's Anett Kontaveit 7-5, 6-4, in the second round of the Porsche Tennis Grand Prix on Wednesday in Stuttgart, Germany.
Kontaveit dominated with her serve, recording 12 aces and winning 37 of 43 first-serve points. The WTA's No. 27-ranked player, Kontaveit was the runner-up in Stuttgart in 2019.
Defending champion Petra Kvitova, the No. 7 seed, advanced with a 6-3, 3-6, 6-3 win over Maria Sakkari in a clash of top-20 players in the world. Kvitova, who saved 13 of 16 break points, only managed to break Sakkari's serve once in the second set but rebounded in the third to win the last three games of the match.
Top-seeded Ash Barty endured a back-and-forth second set with Laura Siegemund to win her second-round match 6-0, 7-5.
TEB BNP Paribas Tennis Championship Istanbul
Katerina Siniakova of the Czech Republic defeated French challenger Kristina Mladenovic in the second round at Istanbul 6-4, 3-6, 6-4, in a match that took 2 hours, 28 minutes.
Siniakova fell behind 5-1 in the second set as Mladenovic cruised, but she regained control to start the third by breaking Mladenovic's serve in the first game. Siniakova saved 13 of 20 break points while converting 7 of her 13 opportunities to break Mladenovic.
Marta Kostyuk of Ukraine upset No. 4 seed Daria Kasatkina of Russia 6-3, 7-5, and Ana Konjuh of Croatia took down No. 8 seed Qiang Wang of China 6-1, 6-4. Romania's Sorana Cirstea will join those winners in the third round after a tight victory over Russia's Anastasia Potapova, 7-6 (6), 6-4.
--Field Level Media