Second seed Ratchanok Intanon advanced to the quarter-finals of the Bitburger Open on Thursday with victory over German qualifier Olga Konon.
The 20-year-old Thai came through a tight first game before dominating the second for a 24-22 21-9 victory in 37 minutes.
She moves on to face Maria Febe Kusumastuti of Indonesia, who earlier edged Porntip Buranaprasertsuk 13-21 21-19 24-22.
Third seed Nozomo Okuhara also advanced, dispatching Hsu Ya Ching 21-9 21-8.
Her next opponent will be Thailand's Busanan Ongbumrungphan, who was similarly dominant in her 21-7 21-6 victory over Ksenia Polikarpova.
Akane Yamaguchi will also fly the Japanese flag in the last eight, having beaten Jing Yi Tee 21-18 21-17.
She faces Beatriz Corrales, who was a 21-18 20-22 21-14 winner over Line Kjaersfeldt.
The remaining quarter-final will see unseeded pair Kirsty Gilmour of Scotland and Natalia Koch Rohde of Denmark battle it out for a place in the last four.
In the women's doubles, the highest-ranked pair in the field, Indians Jwala Gutta and Ashwini Ponnappa, went down 23-21 13-21 26-24 to Dutch duo Samantha Barning and Iris Tabeling.