Neither side was able to open the scoring in the first half, but Vietnam finally broke the deadlock eight minutes from time. Throwing bodies forward in search of an equaliser, the Thais left themselves exposed at the back and the Vietnamese made sure of a win with a second goal in the stoppage time.
Coming second in the group means that Thailand are likely to face a more difficult opposition in the semi-finals on August 2, in the form of an Australia U-20 side that beat Timor-Leste 20-0. A daunting task, but one Thailand must face if they intend to defend their crown.