Defending champions, Sania Mirza and Cara Black knocked out Martina Hingis and Belinda Bencic in straight sets to reach the semifinals of the WTA Toray Pan Pacific Open Tennis at Tokyo on Thursday. Sania and Cara needed 62 minutes to dispatch the Swiss pair 6-4, 6-2 in the quarterfinals.The top seeded Indo-Zimbabwean pair broke the rivals seven times but also lost its serve four times in the contest. They next face Serbian-Spanish combine of Jelena Jankovic and Arantxa Parra Santonja.