Chen Yufei of China competes during the women's singles quarterfinal match against Akane Yamaguchi of Japan at the BWF (Badminton World Federation) World Championships 2018 in Nanjing, capital of east China's Jiangsu Province, Aug. 3, 2018. Chen Yufei lost 1-2. (Xinhua/Li Xiang)

Akane Yamaguchi of Japan competes during the women's singles quarterfinal match against Chen Yufei of China at the BWF (Badminton World Federation) World Championships 2018 in Nanjing, capital of east China's Jiangsu Province, Aug. 3, 2018. Akane Yamaguchi won 2-1. (Xinhua/Li Xiang)

Akane Yamaguchi of Japan competes during the women's singles quarterfinal match against Chen Yufei of China at the BWF (Badminton World Federation) World Championships 2018 in Nanjing, capital of east China's Jiangsu Province, Aug. 3, 2018. Akane Yamaguchi won 2-1. (Xinhua/Li Xiang)

Akane Yamaguchi of Japan competes during the women's singles quarterfinal match against Chen Yufei of China at the BWF (Badminton World Federation) World Championships 2018 in Nanjing, capital of east China's Jiangsu Province, Aug. 3, 2018. Akane Yamaguchi won 2-1. (Xinhua/Li Xiang)

Chen Yufei of China competes during the women's singles quarterfinal match against Akane Yamaguchi of Japan at the BWF (Badminton World Federation) World Championships 2018 in Nanjing, capital of east China's Jiangsu Province, Aug. 3, 2018. Chen Yufei lost 1-2. (Xinhua/Li Xiang)

Akane Yamaguchi of Japan competes during the women's singles quarterfinal match against Chen Yufei of China at the BWF (Badminton World Federation) World Championships 2018 in Nanjing, capital of east China's Jiangsu Province, Aug. 3, 2018. Akane Yamaguchi won 2-1. (Xinhua/Li Xiang)