Fourth-seeded Angelique Kerber of Germany, the highest-ranked woman remaining at the Brisbane International, advanced to the semifinals on Thursday with a 6-4, 6-4 win over Anastasia Pavlyuchenkova of Russia.

Top-seeded Simona Halep and No. 3-seeded Maria Sharapova withdrew injured ahead of their matches on Tuesday, while second-seeded Garbine Muguruza of Spain retired with an injury in the second set of her match Wednesday.

At another Australian Open warm-up tournament, Austria's Tamira Paszek became the first player to reach the ASB Classic semifinals in Auckland, New Zealand, when she beat Kirsten Flipkens 6-4, 6-7 (3), 6-3 in a match between qualifiers that lasted 2 hours, 51 minutes.

Paszek, an Auckland semifinalist in 2008 as a teenager, saved a break point in the final game before finally converting her eighth match point.