Auckland: Top-seeded Sabine Lisicki retired from her quarterfinal match in the ASB Bank Classic on Thursday because of a back injury, compromising her preparation for the Australian Open.
Lisicki, ranked 15th, trailed unseeded German compatriot Angelique Kerber 6-4, 4-3 when she withdrew. The 22-year-old player left the court after the first set to receive treatment.
Kerber will face fourth-seeded Flavia Pennetta in the semifinals. Pennetta beat Elena Vesnina 6-2, 6-1.