Lee Chong Wei of Malaysia returns a shuttlecock during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Lu Hanxin)

Lee Chong Wei of Malaysia competes during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Lu Hanxin)

Lee Chong Wei of Malaysia returns a shuttlecock during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Lu Hanxin)

Lee Chong Wei of Malaysia returns a shuttlecock during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Bai Xuefei)

Lee Chong Wei of Malaysia celebrates during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Bai Xuefei)

 Lee Chong Wei of Malaysia competes during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Lu Hanxin)

Lee Chong Wei of Malaysia celebrates during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Bai Xuefei)

Lee Chong Wei of Malaysia reacts after men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Bai Xuefei)

Lee Chong Wei of Malaysia returns a shuttlecock during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Lu Hanxin)

Lee Chong Wei of Malaysia returns a shuttlecock during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Bai Xuefei)

 Lee Chong Wei of Malaysia celebrates during men's single semifinal match against Du Pengyu of China at the 2013 BWF World Championships in Guangzhou, capital of south China's Guangdong Province, Aug. 10, 2013. Lee Chong Wei won 2-1. (Xinhua/Bai Xuefei)