Yihan has proven a challenge for Nehwal in the past, possibly because she is so tall, and the bronze medallist has only won once in their nine meetings and then because the Chinese player retired injured.
Ahead of their quarter-final Nehwal said: "I try to look at how opponents are catching me. Not many players catch me, but I am trying to improve."
Fellow Indian shuttler Arvind Bhat added: “The problem is Saina comes up against very few tall players of that level so it’s about getting used to her game during a match. Saina’s trajectory from drop shots up will lack the elevation. It has to go higher when she hits."
The world number three booked her place in the quarters with a victory over Indonesia's Bellaetrix Manuputty followed by a 21-15 21-15 win over South Korean qualifier Kim Hyo Min.