Josef Martinez netted a hat trick and Miguel Almiron scored twice as Atlanta won the battle of the expansion franchises amid heavy snowfall in Minnesota.
Atlanta impressed in last week's opener before it was overpowered by the New York Red Bulls but there was no repeat Sunday after racing to a 3-0 lead before the half-hour mark.
Martinez scored twice in that period, including the third-minute opener, while Almiron was also on target.
Kevin Molino pulled a goal back for Minnesota from the penalty spot in the 30th minute but that is as good as it got for the hosts as Atlanta pilled on three unanswered goals in the second half, with Jacob Peterson joining in on the action at the death.
Rodney Wallace and Maximiliano Moralez also found the back of the net for the hosts at Yankee Stadium.
Diego Chara scored the lone goal in a match that saw Galaxy captain Jelle Van Damme sent off in the first half.