Thailand beat Vietnam twice, first in their opening match in the Pool D group round-robin preliminaries in Nakhon Ratchasima before delighting home fans with a 3-1 (25-11 22-25 25-19 25-8) comeback.
It is the first time that Vietnam have been ranked fourth in the Asian meet, ahead of the Republic of Korea (world junior No 18), Chinese Taipei (world junior No 21) and Kazakhstan (world junior No 26).
In the final match, China crushed Japan 25-20, 21-25, 25-22, 14-25, 16-14 to win the event.
The dramatic victory handed China their 12th title in the biennial top competition. By becoming the top two teams in the prestigious tournament, China and Japan have qualified for next year’s FIVB Women’s U20 Volleyball World Championship in Mexico.