The Khel Ratna winner and second seeded Indian player thrashed Russia's Ella Diehl (21-14 21-18) in just 40 minutes in the third round of the women's singles event.
Saina was aggressive from the start and knowing that her opponent Diehl liked long rallies kept the pace slow and killed the game in mid court. Within minutes of the start Saina was off to a 10-5 lead as Diehl made errors at the net.
"I wouldn't say that the first game was easy. I felt better than my second round game and I did control the play. I know she would have liked to play long rallies because that is her strength and I didn't allow that," said Saina after the match.
"I think I am more comfortable with the conditions now. But it's going to get tougher now as higher seeded players will come through but I am prepared. It's not that I haven't played quarter-finals before but a World Championship has its own pressures and I think I am used to it," she added.
Saina will next play either 11th seed Jie Yao of the Netherlands or China's sixth seed Shixian on Saturday, Aug 28.