MONCTON, New Brunswick -- Dalibor Dvorsky, Robert Baco and Filip Mesar scored in a 3:19 span in the second period and Slovakia upset the United States 6-3 on Wednesday in the world junior championship.

Libor Nemec, Peter Repcik and Alex Ciernik also scored for Slovakia, and captain Simon Nemec, this year's No. 2 overall pick in the NHL draft by the New Jersey Devils, had three assists in the Group B game.

Adam Gajan made 23 saves to help Slovakia rebound from an opening 5-2 loss to Finland on Tuesday. Wednesday's victory marked just the fifth time Slovakia has beaten Team USA in 21 world junior matchups.

Tyler Boucher, a 2021 first-round pick of the Ottawa Senators and the son of former NHL goaltender Brian Boucher, scored twice for United States. Michigan Wolverines forward Gavin Brindley added a goal, and Colorado College goalie Kaidan Mbereko made 30 saves. The Americans opened Monday with a 5-2 victory over Latvia, but Mbereko did not play in that contest.

The leaders in ice time for both teams were both defenseman, and both Devils prospects. Simon Nemec finished at 25:31, and Luke Hughes, the Team USA captain who was selected No. 4 overall in 2021, closed at an even 25:00.

Team USA will face Switzerland on Thursday, while Slovakia battles Latvia on Friday.

In Group A in Halifax, Nova Scotia, Canada faced Germany in the night game. Canada dropped a 5-2 decision to the Czech Republic in its opener Monday.

The Associated Press contributed to this report.