Belarus took the lead through Dmitry Pankov after just 20 seconds and held their advantage until the second period.
But the home side then stepped up a gear with John Leclair scoring two goals and Brett Hull adding another in the opening eight minutes of the second period.
Final group tables
2. Czech Republic
Hull scored on a slap shot in the first minute of the period then set up Leclair for two goals in less than five minutes - giving his team-mate five goals in three games.
Mike Modano, reunited with Hull, his former Dallas Stars team-mate, also had two assists as the Americans finished the round-robin stage of the competition unbeaten.
Leading 3-1 after two periods, the US then piled on five goals in the third period - including two each by Scott Young and Bill Guerin.
As group winners the US now get to play the lowest-placed team from the other group - Germany - in the quarter-finals.
Meanwhile, Finland claimed second spot in the group with a 3-1 triumph over Russia.
Finland v Canada
Russia v Czech Rep
USA v Germany
Sweden v Belarus
Captain Teemu Selanne scored their first with Mikko Eloranta converting a backhand shot near the end of the second period.
Jiri Lehtinen completed the scoring by poking home a rebound 35 seconds into the third period for a power play goal.
Pavel Bure scored for the Russians who finished a disappointing third in the group.
The Finns will now face Canada in Thursday's quarter-finals after they drew 3-3 with reigning champions the Czech Republic in the other group.