In the first set, Thailand dominated with their strong offensive line that taunted the hosts and easily won 25-14.
That was the cue for the more than 2,500 home fans to turn up the volume and the heat on the Thais, who began to wobble.
The Vietnamese coach also made some tactical changes, subbing three players.
Key player Tran Thi Thanh Thuy formed an attacking trio with Duong Thi Hen and Dang Thi Kim Thanh that constantly scored. Thuy also showed her defensive skills as she and Tran Thi Bich Thuy blocked many of Thailand’s strikes.
Vietnam went on to win the next two sets 25-22 and 25-21.
The fourth set went back and forth, but Thailand made many unforced errors. Vietnam took advantage of this to pull 18-12 ahead before winning 25-14 and with it the match.
The win once again gave Vietnam a bronze medal like they had won in Thailand two years ago.
The third edition of the Asian Women's U23 Volleyball Championship organized by the Asian Volleyball Confederation was played in Hanoi from July 13 to 21.
China won the gold medal and North Korea silver.