Junya Ito scored the solitary goal early in the first half to hand Japan their third win in five games, lifting them to third in the provisional table on nine points, just behind Saudi Arabia and Australia.
Meanwhile, with their fifth consecutive defeat, Vietnam remained at bottom in the group on zero points.
Japan proved their power as a World Cup regular by dominating from the start, with an Osako header forcing goalkeeper Bui Tan Truong to make a comfortable save after 11 minutes.
Moriyasu Hajime's side needed only six more minutes to open the scoring as Minamino set up Ito to tap into an empty net.
Japan almost doubled their advantage at the half hour mark but Morita's shot from outside the box sailed narrowly wide.
The guests added a second goal a few minutes before halftime; however, it was denied due to offside rule.
After the break, Vietnam managed to produce a number of opportunities but could not convert any of them into an equaliser.
Notably, Luong Xuan Truong wasted a clear-cut chance late in the match skewing a shot high in an unmarked position.
Meanwhile, keeper Bui Tan Truong was forced to make several saves from attempts by Ito (61') and Shibasaki (81', 85').
Next up for Vietnam will be another home clash against Saudi Arabia on November 16.
(Source: NDO)