The 2015 champions went ahead in the second period thanks to Matthew Barzal, before Colin White restored parity for the Americans shortly after in a topsy-turvy Group A clash.

Zach Werenski then turned the contest on its head by edging the United States into a 2-1 lead but the Canadians hit back as Dylan Strome found an equaliser.

The joy for Canada was short-lived, however, as Louis Belpedio found the net with an effort from distance to put the Americans on the brink of victory late on, and their success was sealed when Auston Matthews added a fourth goal.

“Getting Canada right off the bat, we needed to be ready,” Matthews said.

“I think everybody played well - we were up for the challenge.

“It was a good win for us.”

Sweden, fourth at the 2015 event in Montreal, moved to the summit of Group A as they hammered Switzerland 8-3, though their victory was somewhat marred by injuries to star players William Nylander and Adrian Kempe.

In Pool B, hosts Finland got their campaign off to the best possible start, delighting the crowd inside the arena by claiming a rampant 6-0 win over Belarus.

Jesse Puljujärvi was the pick of the home nation’s performers as he bagged a two-goal salvo to help his side to a convincing triumph, with Patrik Laine, Sebastian Repo, Mikko Rantanen and Sami Niku also getting on the scoresheet.

Russia, beaten 5-4 by Canada in the 2015 final, also began with victory as they shaded a tight contest with the Czech Republic, emerging with a 2-1 shootout win.

After a nervy encounter finished 1-1 following regulation time, Maxim Lazarev proved to be the hero for the Russian side as he scored the deciding shootout goal, with goaltender Alexander Georgiev saving all three Czech efforts.

The tournament in Helsinki continues tomorrow with two matches as Slovakia make their bow at the event when they play Belarus in Group B before Switzerland entertain Denmark in Group A.