Singapore: Twin Olympic medallist PV Sindhu sailed into the women's singles quarterfinals of the USD 1,000,000 Singapore Open Super 750 badminton tournament with a straight-game win here on Thursday.Sindhu took just 37 minutes to get the better of Riko Gunji of Japan 21-9 21-12 in her second round match.But a stern test awaits Sindhu as she is pitted against top seed An Se Young of Korea in the last-eight round.The fourth seeded Indian men's doubles pair of Satwiksairaj Rankireddy and Chirag Shetty, however, had to sweat it out to progress to the quarterfinals, beating Chinese Taipei duo of Lee Jhe-Huei and Yang Po-Hsuan 21-15 11-21 21-18 in a contest that lasted exactly an hour.Satwik and Chirag will next face Malaysia's Khai Xing Kang and Aaron Tai.The Indian mixed doubles pair of Dhruv Kapila and Tanisha Crasto too progressed to the quarterfinals, beating Japanese combination of Yuta Watanabe and Maya Taguchi 8-21 21-17 21-16.They will next meet the winner of the match between Korean pair of Kim Jae Hyeon-Jang and Ha Jeong and third seeded Malaysian combination of Chen Tang Jie and Toh Ee Wei.