Meanwhile, other Indians in the men's singles fray -- Kidambi Srikanth and H S Prannoy -- also made it to the pre-quarterfinals with straight-game victories.
The second seeded Saina, who got a bye in the first round, had an easy start to her campaign as she took just 34 minutes to overcome Hong Kong's Cheung Ngan Yi 21-13 21-9 in a second round match.
The world No. 2 Indian won a total of 42 points as compared to just 22 by her opponent.
The second game also went on similar lines as Saina never let her rival come even close to her. It was a matter of time before she sealed it 21-9.
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World No. 3 Srikanth, who won the India Super Series this year, defeated Chinese Taipei's Hsu Jen Hao 21-14 21-15, while world No. 12 Prannoy beat Uganda's Edwin Ekiring 21-14 21-19 in another lop-sided contest.
The Commonwealth Games champion Kashyap, seeded 10th, played out of his skin but could not get past 32-year-old Tien Minh Nguyen of Vietnam, losing 21-17 13-21 18-21 in a tough encounter that lasted an hour and five minutes.
There was good news for 2011 World Championship bronze medallist pair of Jwala Gutta and Ashwini Ponnappa as the 13th seeds beat Chinese Taipei pair of Hsueh Pei Chen and Wu Ti Jung 21-10 21-18 in women's doubles competition.
Among other Indians in fray, women's doubles combo of Pradnya Gadre and Sikki N Reddy suffered a 17-21 19-21 loss to 14th seeded Japanese combo of Shizuka Matsuo and Mami Naito, while Pranaav Jerry Chopra and Akshay Dewalkar went down 16-21 12-21 to Denmark's Mads Conrad-Petersen and Mads Pieler Kolding in the men's doubles event.