Son surprisingly crashed out of the tournament at the first hurdle as he was on the wrong side of a 21-19, 11-21, 21-13 reverse against the unseeded Japanese player at the Innogy Sporthalle in Mülheim.

Son's team-mate Lee Hyun-il awaits for Nishimoto in the next round tomorrow.

China's Shi Yuqi had no such trouble as he progressed to the second round by overcoming compatriot Zhao Junpeng with a hard-fought 21-17, 16-21, 21-19 success.

Yuqi, the Nanjing 2014 Youth Olympic Games champion, was joined in round two by fourth seed Chou Tien Chen of Chinese Taipei.

Chou dispatched South Korea's Jeon Hyeok-jin 21-18, 21-11 to set up a meeting with Subhankar Dey of India.

Wang Tzu Wei of Chinese Taipei, who won two gold medals at last year's Summer Universiade on home soil, was another high-profile casualty in the men's singles draw as he was beaten 21-18, 21-15 by Japan's Kento Momota.

Momota's reward for knocking out the seventh seed is a clash with Thailand's Suppanyu Avihingsanon, who ousted Chinese Taipei's Hsu Jen Hao 21-15, 22-20.

In the women's singles tournament, second seed Sung Ji-hyun of South Korea cruised into round two with a 21-12, 21-16 win over Indonesia's Fitriani Fitriani.

Sung's compatriot Kim Hyo-min awaits after she beat Thailand's Pornpawee Chochuwong 21-18, 21-19.

Chen Yufei of China, the fourth seed, also safely progressed by defeating Malaysia's Sonia Cheah 21-11, 21-13.

Turkey's Neslihan Yigit claimed an epic 21-15, 14-21, 21-19 victory against Denmark's Mette Poulsen and will face Chen in the second round.