The 25-year-old world champion broke two Olympic records in the process, lifting 117 kg in the clean and jerk, and finishing with a total score of 212 kg.
The early first gold for the host nation came after a lavish opening ceremony, which was overshadowed in international media by fighting between Georgian and Russian troops in Georgia's separatist republic of South Ossetia.
The International Olympic Committee voiced regret on Saturday that the traditional Olympic truce had been broken, and called on the sides to resolve the conflict through dialogue.
China had been expected to win its first gold medal in the women's 10-meter air rifle competition, in which Du Li was the favorite. However, she finished fifth, leaving Katerina Emmons of the Czech Republic to claim the first gold medal of the games.
