Sixth-seeded Saina hardly broke sweat as she outclassed Iran's Soraya Aghaeihajiagha 21-7, 21-6 in just 18 minutes in her round of 16 match.
In the first game, Saina allowed the rallies to go a little longer as she took 14 minutes to win 21-7.
A ruthless Saina completely decimated the Iranian, finishing her off in the second game 21-6 in an unbelievable four minutes.
Saina's younger compatriot P.V. Sindhu, world No.10 and eight seed, failed to live upto expectations as she was ousted 22-20, 16-21, 20-22 by Indonesia's Bellaetrix Manuputty in an hour and two minutes.
A ruthless Saina completely decimated the Iranian
Sindhu, two-time World Championships bronze medallist, looked completely in control till the halfway mark of her pre-quarters, winning the first game and taking a comfortable 10-2 lead in the second.
The 19-year-old, however, suddenly lost the plot and allowed the Indonesian, ranked 34th in the world, to get back into the match.
Sindhu uncharacteristically made numerous unforced errors as Bellaetrix wrapped up the game 21-16.
The Indian failed to get her rhythm back and lost early ground in the decider. Sindhu made a mini-comeback to lead 17-16 but squandered the lead again before giving the Indonesian the first match point.
The Hyderabadi shuttler managed to save the match point but failed to do so on the second and crashed out of the Games.