Khosit Phetpradab could not reproduce his impressive run at last week's Japan Open, losing to top-ranked Viktor Axelsen of Denmark in the first round of the China Open yesterday.
Axelsen needed only 30 minutes to finish off the world No.26 Thai 21-12, 21-15 in the BWF World Tour Super 1000 at the Olympic Sports Center Xincheng Gymnasium in Changzhou, Jiangsu.
In Japan last week, Khosit defeated All England winner Shi Yuqi and Olympic champion Chen Long, both of China, on his way to the final.
He lost to home favourite Kento Momota, the newly-crowned world champion, in the title match.
Kantaphon Wangcharoen, Thailand's highest-ranked male player at No.20, reached the second round in China after defeating Hans-Kristian Solberg Vittinghus of Denmark 21-18, 21-18.
Chinese great Lin Dan suffered a shock 2-1 loss to Indonesia's Anthony Sinisuka Ginting.
Ginting nearly blew a healthy lead against Lin, allowing his rival to take the match to a sticky endgame before escaping from his grasp 22-24, 21-5, 21-19.
Another player to escape likely defeat was home icon Chen Long, who looked down and out against young compatriot Huang Yuxiang at 15-19 in the second game, but suddenly woke up to take the next six points in a row before demolishing his opponent in the third for a 20-22, 21-19, 21-13 win.
In the women's singles, Busanan Ongbamrungphan comfortably beat Beatriz Corrales of Spain 21-12, 21-16.
In other women's singles action, second seed Akane Yamaguchi of Japan held off a determined charge from Malaysia's Goh Jin Wei 23-21, 12-21, 21-15.
Yamaguchi's compatriot Aya Ohori, third seed Pusarla Sindhu of India and fifth seed Chen Yufei of China also made their way into the second round.
In the women's doubles, sixth seeds Jongkolphan Kititharakul and Rawinda Prajongjai were upset by Maiken Fruergaard and Sara Thygesen of Demark 21-17, 12-21, 21-18.
Meanwhile, fourth seed Ratchanok Intanon begins her campaign against Beiwen Zhang of the US and Nitchaon Jindapol faces China's Cai Yanyan today.