Thursday matches of Vietnam vs Thailand and Indonesia vs Laos will decide who will go further in the tournament.
Indonesia, now second in group B, hold a more certain chance given their weaker opponents.
Vietnam have to at least draw Thailand to secure their group top position, or lose by no more than one goal difference to enter the next round, on Saturday.
Myanmar has entered the semifinals as top of Group A, and Cambodia second.
Photos by Lam Thoa, Duc Dong