Thailand secured the win with a score of 25-17, 21-25, 32-30, 25-21.
The third set was crucial, with a two-point clear margin needed to win the set after the teams reached a tie at 25-25.
Despite the best efforts of Vietnam's 1.93m-tall Trần Thị Thanh Thúy and her wicked smashes, the experience of the world's 15th-ranked side made the difference.
Thailand's Soraya Phomla returned to the squad following a lengthy lay-off with injury and was welcomed by the younger members of the team, telling Olympics.com after the match, "This is my first time back in the national team and I'm so excited."
A gold medal alongside her team-mates is quite the reward for her perserverance.