No. 1 Azarenka withdraws from Pan Pacific Open

TOKYO (AP) - Top-ranked Victoria Azarenka withdrew from the Pan Pacific Open quarterfinals on Thursday, a day after experiencing dizziness in a third-round win over Italy's Roberta Vinci.

Azarenka's scheduled opponent on Thursday, fifth-ranked Angelique Kerber of Germany, advanced to the semifinals on a walkover.

Azarenka, playing in her first tournament since losing in the U.S. Open final to Serena Williams, had her blood pressure checked midway through the first set of Wednesday's match but bounced back.

The Belarusian said she has been struggling with her health since arriving in Japan.