French forward Olivier Giroud scored a first-half hat trick, getting the opener after just five minutes, and following up with two goals in rapid succession just before half-time.
Giroud, who joined Arsenal in June 2012 from Ligue 1 champions Montpellier, now has five goals in two games on the Gunners’ Asian tour, after scoring twice in Sunday’s seven-goal win over the Indonesian Dream Team in Jakarta.
Arsenal turned in exhibition stuff as they repeatedly pierced a spirited Vietnamese defence.
After a flurry of half-time substitutions on both teams, teenager Alex Oxlade-Chamberlain scored Arsenal’s fourth a minute after the restart.
Arsenal’s pacy front man Chuba Akpom scored in minute 56 and again on the hour after Oxlade-Chamberlain passed the ball across to the young striker, who also hit the target against the Indonesians.
Spanish midfielder Mikel Arteta, a 2011 signing from Everton, scored Arsenal’s seventh in the 75th minute.
Tran Manh Dung scored a consolation in the 78th minute, delighting the home crowd, who went wild as the Vietnamese forward stripped off his shirt and ran across the pitch in celebration.
It began to pour with rain as a monsoon hit in the final minutes of the game, prompting many of the cheering Vietnamese fans to run for cover, leaving sections of the stands empty.
Vietnam’s goalkeeper Tran Buu Ngoc was handed a red card in the 89th minute after he came out of his area, was beaten to the ball but won it with his hand.
Vietnamese defender Dao Van Phong went into goal for the final minutes.
England striker Theo Walcott took the resulting free kick for Arsenal but put it wide.
Arsenal next head to Japan, where their visit includes a game against Wenger’s former club, Nagoya Grampus.