The third seeded Indian prevailed 21-19 21-6 in a 39-minute contest against the fifth seed, who had an intimidating 8-1 overall record against Saina before the match.
Saina will now face another Chinese Sun Yu in the last-four stage. Yu advanced after her Thai rival, eighth seed Ratchanok Intanon, retired midway through the match with the Chinese player leading 21-11 19-21 19-13.
It was an impressive performance by Saina in her quarterfinal match as she got past Yihan, whose only previous loss to the Indian was forced by injury.
The second game was Saina all the way as Yihan crumbled rather inexplicably.