Substitute striker Thanh Binh scored a double in the second half after his teammates Ngoc Son and Trieu Viet Hung netted one each in the first 45 minutes.
The only goal for the U-19s went to Viet Cuong who was on the field after the interval.
The win pushed Vietnam to second place in the ranking with seven points and ensured them a berth in the final ignoring their last round robin format match against Yokohama FC on December 20.
Yokohama continued their winning streak beating Myanmar 5-0 in an earlier match on December 18.
In previous games, they beat Vietnam’s U19s 3-1 and Thailand 2-0.
The Japanese side forced Myanmar squad to follow their pace and easily beat them with goals by Hashimoto Kento, Kamiyama Kyousuke, a double from Matsuoka Rimu in the second half and Maejima Yota 10 minutes before the end.
Yokohama, topping the table with nine points, earned a berth in the final with one game in hand.
