Vuong Thi Binh, Nguyen Thi Thu Ha and Nguyen Thi Huyen gained 9.996 points to overcome their Brunei rivals.
Ha and Huyen also clinched a silver in the women's double of seni while Riska Hermawan and Ririn Rinasih of Indonesia bagged gold.
Speaking to reporters, Ha said she has been waiting for a gold medal for 14 years and this is her best achievement at a SEA Games, especially the one hosted by Vietnam.
Vietnam secured one gold, one silver and three bronzes in six seni category at this SEA Games.
Ten events of pencak silat’s tanding (match) are slated for May 13 in Hanoi’s Bac Tu Liem Gymnasium.
SEA Games 31, themed “For a Stronger South East Asia”, is being held in the capital and 11 neighbouring provinces and cities until May 23.
Featuring 40 sports with 523 events, it is expected to attract around 10,000 participants. The biennial event was initially slated for late 2021 but delayed due to the COVID-19 pandemic.