Canada and the USA are the only teams with a perfect record at the ice hockey world championships after winning their third games in the group stage on Monday.
The USA went top of Group B, played in the eastern city of Ostrava, after beating defending champions Russia 4-2.
Los Angeles Kings forward Trevor Lewis put the US team 1-0 ahead in the sixth minute.
Russian defenceman Anton Belov levelled the score early in the second period but Boston defenceman Torey Krug scored a second US goal three minutes later.
Arizona forward Marc Arcobello, who swapped teams in the NHL three times this season, raised the score to 3-1 in the 52nd minute.
Sergei Plotnikov narrowed the goal difference four minutes before the end but New York Islanders forward Brock Nelson then found an empty net nine seconds before the siren to round off the score as Russia had pulled Columbus Blue Jackets goalie Sergei Bobrovski.
“Undoubtedly those guys are going to get their chances, their opportunities,” said Krug.
“You can’t stop all of them but we did a pretty good job of keeping that number down.”
“We did well at realising when we had to calm the game down, get the puck out of the zone.”
In Group A, played in Prague, Canada beat the Czech Republic 6-3 a day after humiliating Germany 10-0.
Edmonton forward Jordan Eberle scored four minutes into the game and his NHL teammate Taylor Hall added another on 19 minutes, but the Czechs narrowed the lead through Arizona wing Martin Erat before the first intermission.
The home fans went frantic as Martin Zatovic put the Czechs level in the 36th minute, but their joy was short-lived as Philadelphia forward Sean Couturier handed the star-packed Canadian team a lead two minutes later.
Dallas Stars young gun Tyler Seguin and Pittsburgh Penguins star Sidney Crosby scored power-play goals in the last period.
Former St Louis Blues forward Vladimir Sobotka narrowed the difference, only for Los Angeles forward Tyler Toffoli to round off the score a minute before the final siren.
In the first Group A game of the day, Boston forward Loui Eriksson scored a hat-trick as Sweden thrashed underdogs Latvia 8-1.
Joel Lundqvist, playing for Frolunda in the Swedish league, had a goal and an assist while Arizona defenceman Oliver Ekman-Larsson assisted twice.
In the evening game in Group B, Finland beat Norway 5-0.
Finland forward Joonas Kemppainen scored twice and added an assist and defenceman Esa Lindell had a goal and two assists while Nashville goalie Pekka Rinne stopped 20 shots for his second shutout of the tournament.