Ratchanok Intanon upset world No 1 Tai Tzu Ying of Taiwan 10-21 21-9 22-20 in the quarter-finals of the Tahoe China Open in Fuzhou China on Friday.
After losing the opening game due to uncharacteristic errors, Ratchanok raised her level to take the second game to level the tie. Thanks to a barrage of unforced errors from her opponent.
In the topsy-turvy final game, Ratchanok needed up to four match points before she could knock out the world No 1 in the end, generating two great shots to wrap up the encounter that last more than hour.
She will take on Akane Yamaguchi of Japan on Saturday in the semi-finals.