What are Vietnam U19's chances of advancing after their loss to Indonesia U19?

Losing 1-2 to Indonesia U19 leaves Vietnam U19 in second place of Group A, requiring them to evaluate their performance against the second-placed teams from Groups B and C to decide who reaches the semifinals.

After the group stage, Vietnam U19 has 6 points, a goal difference of 9-2 (+7), and sits second in Group A. In Group B, Thailand U19 and Malaysia U19 each have 6 points ahead of their direct clash in the final group match on June 8. Thailand's goal difference is +13, while Malaysia's is +7.

However, because Group C has only three teams, according to the rules, results against the last-placed teams in Groups A and B are excluded when comparing the runners-up to find the best-performing second-placed team.

Thus, Vietnam U19's 3-0 win over Timor-Leste is not counted, leaving them with only 3 points and a goal difference of 6-2 when compared to other runners-up: Malaysia (3 points, goal difference 3-0) and Cambodia (3 points, goal difference also 3-0). Vietnam U19 is currently the best runner-up.

Therefore, Vietnam U19 will reach the semifinals if, in the final round of Group B, Thailand U19 beats Malaysia U19 and Australia U19 beats Cambodia U19.

If at least one of Malaysia and/or Cambodia secures a draw, they will have 4 points and advance, while Vietnam U19 will be eliminated due to fewer points.

If Malaysia beats Thailand and Australia beats Cambodia, then Thailand will finish second in Group B with only 3 points, and one of their wins against Singapore or Brunei will not be counted.

If Singapore beats Brunei in the final round, Thailand U19's 9-0 win over Brunei will be excluded, and Vietnam U19 will then qualify for the semifinals.

If Brunei beats Singapore in the final round, Thailand U19's 4-0 win over Singapore will be excluded, but they are likely to still advance due to a superior goal difference over Vietnam U19. Thus, it is clear that Vietnam U19's chances of reaching the semifinals of the 2026 Southeast Asian Championship are extremely slim.