The spot was secured after Vietnam bagged four more gold medals in swimming, sabre, cycling and wushu, bringing its total gold to 8. The country also earned a total 5 silver and 9 bronze medals.
Malaysia remained on top of the tally with 24 gold, 19 silver and 15 bronze medals, followed by Singapore (13 gold, 13 silver and 11 bronze medals).
Brunei and Cambodia were at the bottom of the list with 4 and 3 bronze medals respectively, while Timor Leste was yet to seize any medal.
Vietnam sent more than 470 athletes to compete at the Games from August 19-30. They are scheduled to take part in 32 out of 38 sports and set to bring home 49-59 gold medals to rank in the top three.