In Jordan Thursday, in the first match 18-year-old Vu Ha Minh Duc played 16-year-old Nawaf Rashed and lost in two straight sets.
In the second match Vietnam’s number one Ly Hoang Nam easily beat an even younger opponent, 14-year-old Nawaf Mashari, also in two sets to level the scores.
In the decider, a men's doubles match, Nam and Le Quoc Khanh easily beat Rashed and Zayed Mousa Shanan to clinch the tie and, with it, take top spot in pool B to advance to the play-offs.
Vietnam had earlier beaten Pacific-Oceania.
In the Asia-Oceania zone group 3 play-offs in Jordan on Saturday, the top two teams from pools A, B and C will play and three will qualify for the Davis Cup World group 2 play-offs.
Vietnam's opponents will be decided through a draw on Friday.