Surrounded by a sea of bright red Chinese flags in the crowd, Zheng knelt on the court and screamed with his arms outstretched while Yaqiong collapsed to the ground before running into her coach's arms as they celebrated victory.
Japan's Arisa Higashino and Yuta Watanabe took the bronze by beating South Korea's Chae Yu-jung and Seo Seung-jae.
The battle for bronze was tight before Watanabe and Higashino pulled clear in the first game, going on to win 21-13 22-20.