The Thai world junior No 1 hit 15 winners to beat the eighth seed, who had earlier ousted former Thai No 1 Salakjit Ponsana in the second round.
“She played fast and attacked constantly but could not maintain her consistency. I just tried to stay in the rallies and wrong-foot her to gain points,” said the world No 19, who was to take on third seed Carolina Marin of Spain last night.
Busanan will be eager to snap her losing streak against the world No 20, after going down to the Spaniard 21-8 21-16 in the Indonesia Open in June and 21-12 17-21 21-14 in the World Championships in August.
“She is a lefty and has powerful smashes. I need to defend well and wait for opportunities to go for my shots,” said the Thai.