seeded Maria Sharapova was forced to retire in the first set of her quarterfinal match against Petra Kvitova at the Pan Pacific Open Thursday. With her Czech opponent leading 4-3 in the first set, Sharapova twisted her left ankle when serving in the eighth game. She limped to her chair and pulled out after seeing a trainer. Kvitova will now face fourth-ranked Vera Zvonareva of Russia, who defeated Maria Kirilenko 6-3, 6-3, in Friday's semifinals. Third-seeded Victoria Azarenka of Belarus beat seventh-seeded Marion Bartoli 7-5, 6-0 to reach the last four. She will next face Agnieszka Radwanska, who beat Kaia Kanepi 6-2, 7-6 (7). Almagro, Troicki in quarters Top seeds Nicolas Almagro and Viktor Troicki both swept into the quarterfinals of the Malaysian Open in straight sets Thursday, joined by former champion Nikolay Davydenko. Almagro, seeded No. 1, posted a 7-6 (7/2), 7-6 (7/4) defeat of compatriot Albert Ramos, while Serbian third seed Janko Tipsarevic also put out Italian Flavio Cipolla 6-2, 6-4. Serbia's Troicki, seeded second, beat Denis Istomin of Uzbekistan 6-1, 6-4 while 2009 champion Davydenko put out Poland's Lukasz Kubot 6-3, 7-6 (7/2) indoors at the Putra stadium. Troicki, a member of the Serbian team that lost to Argentina in the Davis Cup semi-finals, earned revenge for a defeat at the hands of Istomin in the 2010 New Haven semifinals. “I lost to him in a strange match last year. I knew I had to play more offensive and take my chances when they came,” said the 15th-ranked Serb, who will next face Russian Dmitry Tursunov. “Today in the first set I played pretty well and stayed in control. The second set was equal. I was a bit more focused at the end and broke to win the match.”
