Unseeded trio Khosit Phetpradab, Suppanyu Avihingsanon and Kantaphon Wangcharoen all won their second round matches at the Nimibutr Stadium in the capital.

The Super 500 event has been thrown wide open as the top three seeded players withdrew, including China's reigning Olympic champion Chen Long.

Phetpradab knocked out England's former European champion Rajiv Ouseph 23-21, 21-13 to reach the last eight.

Avihingsanon proved too strong for Malaysia's Lee Zii Jia, 21-18, 21-12, while Wangcharoen beat his compatriot Sitthikom Thammasin 21-11, 21-9.

A fourth Thai player was denied the right to reach the last eight as Indonesia's Tommy Sugiarto came from behind to knock out Tanongsak Saensomboonsuk, 19-21, 21-18, 21-16.

In the women's draw there is no home interest in the last eight but the top two seeds do remain in.

Top ranked Akane Yamaguchi of Japan beat Goh Jin Wei of Malaysia 21-15, 21-12 to go through.

India's second seed PV Sindhu, the Olympic silver medallist, dispatched Yip Pui Yin of Hong Kong 21-16, 21-14.

Japan's reigning world champion Nozomi Okuhara, the fourth seed, was another to progress as she beat Thailand's Pornpawee Chochuwong 21-18, 21-15.

The quarter finals will be played tomorrow.