Birmingham, England (SportsNetwork.com) - Five seeds, including Romanian star Simona Halep, secured berths in the quarterfinals at the Aegon Classic tennis event, a grass-court Wimbledon tune-up.

The top-seeded former French Open runner-up handled Czech qualifier Klara Koukalova 6-1, 6-3 in Thursday's third-round action at Edgbaston Priory Club.

Halep's opponent on Friday will be France's Kristina Mladenovic, who upended 10th-seeded Czech Barbora Strycova 7-6 (7-4), 6-2. Strycova was last year's runner-up here to Serbian Ana Ivanovic.

Third-seeded Spaniard Carla Suarez Navarro handled 13th-seeded two-time Grand Slam champion Svetlana Kuznetsova of Russia 6-3, 6-4, while fourth-seeded German Angelique Kerber vanquished 15th-seeded former world No. 1 Jelena Jankovic 6-4, 6-2. Jankovic is a two-time winner here and two-time Aegon Classic runner-up.

In other action involving seeds, No. 6 Czech Karolina Pliskova whipped Kazakhstan's Zarina Diyas 6-2, 6-2 and No. 8 German and former Wimbledon runner-up Sabine Lisicki topped Slovak Magdalena Rybarikova, the 2009 Aegon champ, 7-6 (9-7), 6-4.

Earlier in the day, Pliskova completed a suspended second-round match from Wednesday by finishing off British wild card Johanna Konta 3-6, 6-3, 6-4.

Two other third-round matches saw Czech Katerina Siniakova clip American Christina McHale 6-4, 6-0 and Slovak Daniela Hantuchova best Portuguese qualifier Michelle Larcher de Brito 6-4, 7-5.

Friday's other quarterfinals in Birmingham will pit Suarez Navarro against Pliskova, Kerber versus Siniakova and Lisicki against Hantuchova, the 2013 Aegon champion and 2011 runner-up.

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