Ostapenko sails into Stuttgart quarters

STUTTGART, Germany: Roland Garros champion Jelena Ostapenko continued to build for her Paris title defence with a 6-3, 6-0 win over Zarina Diyas on Thursday at the Stuttgart Grand Prix.

The Latvian was joined in the quarterfinals at the Porsche arena by fifth seed Karolina Pliskova as the Czech beat Russian qualifier Veronika Kudermetova 7-6 (7/4), 6-3. Ostapenko, ranked fifth on the WTA, broke her 52nd Kazakh opponent five times as she won in just 63 minutes. Pliskova, noted for a big serve, hammered 15 aces as she beat Kudermetova in a match that lasted just past the 90-minute mark. The Czech won her first with the number 193rd ranked Russian. Angelique Kerber earned quick revenge against Petra Kvitova with a 6-3, 6-2 defeat of the Czech in the Stuttgart Grand Prix on Wednesday while top seed Simona Halep needed a fightback to survive.

Kerber and Kvitova had faced off last Sunday at the same Porsche arena venue in a Fed Cup semi-final tie won by the visitors, with the Czech star prevailing. The German, a former world number one who is now ranked 12th, was all business against the two-time Wimbledon champion, preventing Kvitova from three straight victories in their head-to-head series. Kerber closed it out on her third match point after 77 minutes when Kvitova returned long.

Top seed Halep, a semi-finalist last year at the tournament, battled to a 4-6, 6-2, 6-3 second round win over Slovakia’s Magdalena Rybarikova.Halep also overcame what appeared to be a hip problem in the first set but did not require a medical timeout.

Kerber set up a match against Anett Kontaveit, the world number 31 who outlasted Kristina Mladenovic 5-7, 7-6 (7/3), 7-6 (7/5). The Estonian needed more than three hours to put out 2017 finalist Mladenovic, with the French player saving match points in the final-set tiebreaker. Between them, the women converted on 19 of 39 break points on offer, with Mladenovic sunk by 10 double-faults. CoCo Vandeweghe put aside her career-long dislike of clay to crush US Open champion Sloane Stephens 6-1, 6-0 with a 56-minute rout.