
The world No 4 ousted the 2017 world junior champion 21-15 21-13, underlining her supremacy over teenager whom she beat in three games in the Indonesian Open in July.
Ratchanok will face reigning world champion Carolina Marin of Spain on Friday. The Thai leads 5-2 in their lifetime record.
In the men’s singles second round, Thai No 2 Khosit Phetpradab beat Mark Calrjouw of the Netherlands 21-14 21-18 to set a clash with Chen Long of China.
Thai top duo Jongkolphan Kititharakul and Rawinda Prajongjai beat Supissara Paewsampran and Puttita Supajirakul 21-13 21-18. They will play top seeded Yuki Fukushima and Sayaka Hirota of Japan in the quarters-finals.