Fourth Seed Saina took just 31 minutes to dispose off Petya 21-18 21-9 and will take on the winner of eighth seed Tine Baun and Japan's Ayane Kurihara in the quarterfinal tomorrow.
In the first game, Saina opened up a four-point lead at 6-2 and though the Bulgarian caught up with her at 12-all, the Indian was successful in keeping her nose ahead to pocket it after a close-fight.
The 21-year-old Indian turned more aggressive in the second game and after leading 5-2 kept taking giant strides forward to widen the gap and eventually took the game away from Petya.
Saina won the Indonesian Open twice on consecutive years in 2009 and 2010.
Published 23 June 2011, 08:29 IST