The first period was scoreless but in the second period, Team USA scored two quick goals with the first from forward Ryan Donoto.
Mark Arcobello scored at the 33:30 mark of the second period to make the score 3-0.
Donato, who also netted two goals against Slovakia in a 2-1 U.S. group-stage victory, blasted a rebound into the far top corner 96 seconds into the second period to put the United States of America ahead 1-0. Ryan Donato scored twice for the USA, while James Wisniewski, Mark Arcobello and Garrett Roe scored one goal each.
The five-goal haul meant the USA scored more against Slovakia than it had in three group stage games combined, while at the other end Ryan Zapolski stopped 21 of the 22 shots he faced. University of Denver hockey star Troy Terry helped the team with three assists.
U.S. college star Troy Terry collected his third assist with 6:30 remaining in the second period, his centering pass blasted home by Mark Arcobello for a 3-0 United States lead.
On Slovakia's next trip down the ice, Ladislav Nagy skated into 31-year-old US goalie Ryan Zapolski, sending him to the ice, but Team USA maintained puck possession for a delayed penalty.More news: Fergie Responds to National Anthem Backlash: 'I Tried My Best'
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The U.S. moves on to face the Czech Republic in a quarterfinal matchup Wednesday night.
Struggling to score goals in their first three games, the Americans struck for three second-period goals to take charge against a Slovak team they also had defeated in the preliminary round.
Midway through the third period Garrett Roe added an insurance goal, set up by Brian O'Neill, and Donato scored one more time.
Goalie Ryan Zapolski stopped 22 of 23 shots for Team USA, while Jan Laco stopped 26 of 31 shots for Slovakia.
The pool stage proved to be a mixed bag for the U.S, who suffered a 3-2 overtime defeat against Slovenia, before beating Slovakia 2-1.