Defending champions Canada thrashed their fierce rivals 5-1 in St Petersburg after Patrick Maroon had put the U.S. in front in the first period on the power play.
Goals from Taylor Hall and Brendan Gallagher gave Canada the lead going into the second period, while the Colorado Avalanche's Matt Duchene made it 3-1.
Canada turned on the style in the third period with Boone Jenner making it 4-1, before Brad Marchand sealed the rout scoring shorthanded to cap an empathetic win for Bill Peters' side.
Russia have never won a world championship on home ice and Oleg Znarok's team have it all to do after a disappointing 3-0 loss to the Czech Republic in Moscow.
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Tomas Kundratek silenced the home crowd in the first period, while Roman Cervenka doubled his side's advantage late on in the second on the power play.
Russia never managed to get going and Czech goaltender Dominik Furch, who plays his club hockey in Russia for Avangard Omsk in the Kontinental Hockey League (KHL), only had to make 17 saves for his shutout.
With roughly a minute and a half left on the clock in the third period, Michal Birner capped a fine night for the visitors with an empty net goal to complete the scoring.
Sweden surprisingly needed overtime to beat Latvia 2-1 with Gustav Nyquist scoring the winning goal, while Finland easily disposed of Belarus 6-2.
(Reporting by Dmitriy Rogovitskiy; Editing by Toby Davis)
