Nolberto Solano’s side, ranked 99 places below Vietnam in the FIFA rankings, took the lead through a superb first-half goal from Mohibullah but could not withstand a second-half onslaught from their opponents.
Long Hai Nguyen, Duc Hoang Nguyen and Bac Dinh Nguyen scored to put Vietnam 3-1 ahead before veteran Kaleemullah Khan pulled one back for Pakistan in the 88th minute. Hoang Minh Williams restored Vietnam’s two-goal advantage in stoppage time.
The result left Vietnam second in Division I Group ‘B’ behind Thailand, with the Philippines third and Pakistan finishing with one point from their three matches in their maiden FIFA competition.
Pakistan had come from two goals down to in their previous match and needed a victory against Vietnam to have any chance of reaching the bronze-medal match.
They dominated the opening half and deservedly went into the break ahead.
Ali Akbar Khan combined with Abdul Samad Shahzad in the opening minutes before his effort inside the box was blocked. Shayek Dost then headed wide in the fifth minute after another promising move through midfield.
Vietnam gradually settled into the game and Yousuf Butt was forced to make a save from a deflected effort, but Pakistan continued to threaten through Ali Akbar and Abdul Samad, who operated down the flanks.
Abdul Samad saw his effort saved before Pakistan took the lead in the 31st minute
Mohibullah pressed a Vietnam centre-back into a mistake, won possession and kept his composure to slot the ball under goalkeeper Patrik Giang Le.
Vietnam nearly equalised before the break when Hoang Minh Williams fired into the side-netting.
Solano introduced Alamgir Ghazi and Umer Nawaz at the start of the second half, replacing Ali Agha and Shayek, but Vietnam quickly turned the game around.
Long Hai Nguyen levelled in the 50th minute, receiving a through ball down the left, cutting inside and firing past Yousuf.
Seven minutes later, Duc Hoang Nguyen completed another attacking move by striking a cutback first time to put Vietnam ahead.
Pakistan responded as Abdul Samad Shahzad saw his effort blocked before being replaced by Abdul Samad Khan. The substitute then delivered a cross from which Umar headed over.
Vietnam extended their lead in the 80th minute when Bac Dinh Nguyen raced onto a long ball and fired past Yousuf.
Pakistan refused to give up and reduced the deficit in the 88th minute. Ali Akbar’s effort went through a crowd of players before Kaleemullah applied the decisive touch.
The comeback hopes were short-lived, however, as Bac Dinh set up Williams to score Vietnam’s fourth and settle the contest.
