The Games run until July 6 and feature 45 nations competing in 12 different sports including kickboxing, short course swimming, futsal and cue sports.
There are ten gold medals available in cue sports and China's Xiao, the world number 37, took one of them on Monday, beating Iran's Amir Sarkhosh 5-4 in the final.
Xiao led 3-0 before his opponent fought back to 3-3. The next two frames were shared then Xiao won the decider 49-0.
Click here for the results and schedules of all the cue sport events.
Ball by ball scoring and results from tournaments