NANJING, Aug. 5 (Xinhua) -- Zheng Siwei and Huang Yaqiong were the better duo in an all-Chinese clash at the BWF World Championships mixed doubles final here on Sunday, beating Wang Yilyu and Huang Dongping 21-17, 21-19 to clinch the gold medal.

With this straight-game victory, Zheng and Huang Yaqiong have extended their winning streak over Wang and Huang Dongping to five matches.

The top seeds withstood a strong fight-back from their rivals in the second game when leading by 14-9, as Wang and Huang Dongping showed tough resistance to close the gap point-by-point and catch up at 19-19.

But Zheng and Huang Yaqiong restored themselves in the key moment, hitting at the gold-medal-point with a smash and eventually wrapping up the victory after Wang's overhand strike was out.

Zheng, with his former partner Chen Qingchen, won the silver medal of the mixed doubles last year in Glasgow. The 21-year-old has paired up with Huang Yaqiong since last October and immediately struck to the gold at the Macao Open.