Ace shuttler Saina Nehwal staved off a scare from Indonesia's Adrianti Firdasari to reach the women's singles quarter-finals in the Singapore Open Badminton Super Series in Singapore City on Thursday. The sixth seeded Indian ace beat 19th-ranked Firdasari 21-18, 17-21, 21-17 in a 50-minute battle to set up a clash with third seed Chinese Lin Wang on Friday.