Srikuta Nirarach scored 12 while Saelao Natnicha tallied 18 excellent sets for Est Cola.
The Thais will face either Nxled or Creamline, which is still playing dethroned PLDT as of press time, in the winner-take-all final slated on Tuesday at the same Cubao venue.
Est Cola is the fourth foreign team to reach the finals and will try to become only the second guest club to win the crown after Japan’s Kurashiki Ablaze won it all in 2023.
The Thais had a hard time shaking off the Vietnamese behind the gritty plays of Dang Thi Kim Thanh and Nguyen Thi Nah Phuong especially in the third frame.
Ho Chi Minh City came back from a 22-24 deficit in the third and forced a deuce after an Est Cola attack error.
Wasan Nattharika answered with a kill before Nirarach’s finishing blow to seal the one-hour, 38-minute victory.
Dang had 14 points and Phuong finished with nine for Ho Chi Minh City, which suffered a fourth loss in five outings.
Meanwhile, Nxled did its part in its bid for a breakthrough championship appearance after beating Farm Fresh, 25-20, 25-21, 18-25, 25-22, for a 3-2 slate.