Jack Johnson scored twice, including the winner 1:47 into overtime as the United States took down Canada, 5-4, at the 2012 World Championship on Saturday.
Patrick Dwyer posted a goal and an assist while Nate Thompson and Jim Slater also scored for the United States, which moved to the top of Group H with five points. Jimmy Howard made 30 saves.
John Tavares, Jeff Skinner, Keith Duncan and Evander Kane all scored for Canada, which trails the United State by one point. Cam Ward turned aside 41 shots.
Tavares took a delay of game call in the extra session when he knocked the puck over the glass and that led to Johnson's wrister that beat Ward for the big win.
It was only the second time since 1985 that the United States has defeated Canada in this event.
Canada hasn't taken home a medal at this event since capturing the silver in 2009 while the United States is seeking its first medal since a bronze in 2004.
In earlier action on Saturday, Russia took a 5-2 win over Latvia while Switzerland downed Kazkahstan, 5-1.
Playing in Stockholm, Sweden, Evgeni Malkin posted two goals and an assist while Ilya Nikulin added a goal and an assist and Semyon Varlamov made 24 saves for the Russians, who failed to capture a medal for the first time in four years in last year's event.
Latvia got goals from Kaspars Daugavins and Miks Indrasis while Edgars Masalskis allowed all five goals on 40 shots.
Mark Streit and Ivo Ruthemann each posted two goals and an assist while Reto Berra made 19 stops for Switzerland, which hasn't taken a medal at this event since 1953.
Roman Savchenko scored the only goal and Vitali Kolesnik gave up all five goals on 34 shots in the loss for Kazakhstan.
The last game on Saturday came from Stockholm and saw Sweden put on a show for the hometown crowd with a 4-1 win over the Czech Republic.
Joel Lundqvist and Niklas Persson each had a goal and an assist while Johan Franzen and Niklas Kronwall also scored for the Swedes, who moved to the top of Group S with the win. Viktor Fasth made 16 stops.
Jakub Petruzalek scored the lone goal while Jakub Stepanek allowed three goals on 19 shots for the Czechs, who had blanked Denmark in the opener on Friday.