The first 45 minutes saw the hosts’ dominate; however, none of their scoring efforts were successfully converted into goals.
Six minutes into the second half, Manh Hung broke the deadlocks with a cunning free-kick that flew past the Singaporean defence wall toward the left side of the goal.
With time running out, Singapore had to play with just 10 players on field after Bin Salleh received a second yellow card for his interference on Vietnam’s Quach Tan, who contributed significantly to the hosts’ remaining goals.
The SHB Da Nang shot past goalkeeper Redzuan to double Vietnam’s lead five minutes after the hour mark before delivering a beautiful pass three minutes later to Ngan Van Dai who made it 3-0 with a powerful finish.
Earlier the same day, defending runners-up, U21 Sydney (Australia) disappointed with a shocking 1-2 loss to U21 Malaysia in their Group B opener.
The tournament, the eighth of its kind, draws the participation of six teams, including U21 Vietnam, U21 Singapore and U21 Thailand in Group A; and U19 Hoang Anh Gia Lai JMG (Vietnam), U21 Malaysia and U21 Sydney in Group B.
At last year’s competition, U21 Vietnam claimed top honours after beating U21 Sydney 4-1 on penalties.
