The mixed pair won twice to top their qualifying group in the mixed doubles at Suwon City’s Indoor Stadium.
Hieu and Sen on April 7 beat Kazaks Samat Yerzhkanov and Veronika Sorokina 21-8 and 21-13 after taking 25 minutes to oust Uzbekistan’s Emil Mirgalautdinov and Kamila Larimova 21-11 and 21-8.
In the next round on April 8, they face Indonesians Marissa Vita and Limpele Landy. This would be a tough match as Vita is seeded fifth in the women’s singles.
The Vietnamese couple of Huynh Nguyen Khang and Vu Thi Trang went straight through to the finals and will face the host country’s Lee Yong-dae and Lee Hyo-jung.
Also through are teammates Thai Thi Hong Gam and Duong Bao Duc, who now face China’s Chen Zhiben and Zhang Jinkang.