The American defenceman floated a long shot that beat Canadian goalie Mason McDonald high to the glove side.
Canada, the defending champion, failed to capitalize with a five-minute power play in the first period, and that proved to be costly in the long haul.
"It was a tough game," said Canada's Jake Virtanen. "They played strong and finished their plays when they got their chances."
It was another exciting, hard-fought tilt between the North American powers, if neither as physical or recklessly offensive as, say, the 31 December, 2008 showdown in Ottawa that Canada rallied to win 7-4 with a John Tavares hat trick.
It was the first time since the 2013 tournament in Ufa, Russia that this round-robin grudge match hasn’t taken place on New Year’s Eve, but the date on the calendar really doesn't matter when these two foes square off.
Depending on what happens when each side faces Sweden (28 December for the Americans, New Year’s Eve for Canada), the result of this game could end up determining the top seed in Group A.
Colin White, Zach Werenski, and Auston Matthews each added a goal and an assist.
"Getting Canada right off the bat, we needed to be ready," said Matthews. "I think everybody played well. We were up for the challenge. It was a good win for us."
Matthew Barzal and Dylan Strome replied for Canada.
The U.S.'s Alex Nedeljkovic won the netminding duel. Shots on goal favoured Canada 27-25.
Unsurprisingly, the teams started at a dizzying pace.
At 1:34, Strome was called for slashing in the offensive zone on Delpedio, but Canada confidently killed it off. Captain Brayden Point was dangerous in the American end, testing Nedeljkovic from the right faceoff circle. Meanwhile, the U.S.’s Sonny Milano was a playmaking dervish with the puck on a string. But there were few bona fide chances.
With just over three minutes left in the period, Canada's Brendan Perlini raised his arms in celebration, thinking he’d beaten Nedeljkovic, but the U.S. goalie got his blocker arm on it and the puck squirted out behind him on the far side of the crease.
At 17:20, Canada got a golden opportunity when an undisciplined Alex DeBrincat got a five-minute major for his flagrant spear on Travis Konecny in front of the Canadian bench. The OHL's leading goal-scorer was out of the game. Yet Canadian coach Dave Lowry’s crew struggled to get organized with the man advantage, often bobbling the puck.
"That’s one of the areas that we talked about before the game," said U.S. coach Ron Wilson. "We’ve got to initiate, not retaliate. That’s the one time, maybe the only time all game that we retaliated."
"It was a big kill," said White.
Canada finally opened the scoring at 5:06 of the second off the rush. Julien Gauthier blocked Chad Krys’s shot attempt at the Canadian blue line and raced away on a 2-on-1. Rourke Chartier couldn’t convert the cross-ice pass, but Gauthier retrieved the puck down low with Nedeljkovic scrambling and sent it to Barzal, who whipped it high into the net.
Strome cut to the slot on the rush with under seven minutes to play in the middle frame and forced Nedeljkovic to make a tough right-pad save. The Canadians kept the Americans hemmed in with savvy puck possession.
After looking out of sync in the early going, Matthews, the projected #1 pick in the 2016 NHL Draft, nearly finessed the puck behind McDonald with four and a half minutes left in the period, but there was nothing doing.
The Americans tied it up at 16:33. Off a faceoff in the Canadian end, Milano fired the puck off the end boards past McDonald’s left post, and it bounced out to White at the opposite edge of the crease. He backhanded it home.
The U.S. carried the play in the early stages of the third. With John Quenneville in the box for interference, Werenski floated one from the line that eluded McDonald high to the blocker at 7:22.
"I made a suggestion to our D about getting the shots through," said Wilson "They managed to do the job in the third period."
Werenski, the U.S. captain, temporarily negated his timely marker when he took a slashing minor while backchecking a couple of minutes later. Strome got the equalizer, sniping one top shelf at 10:45, and a sea of Canadian flags erupted across the arena with cowbells ringing. That joy would be short-lived.
With 2:37 remaining and the U.S. up 3-2, Matthews salted away the victory for Wilson's boys, poking home a loose puck behind McDonald. Bruce Springsteen's "Born in the USA" blasted from the P.A. for the fourth time this night.
"It felt especially good because I haven’t won a game in four years," said Wilson, a two-time Olympic coach who was fired by the Toronto Maple Leafs in 2012. "So what better way to get back on the horse? Beating Canada meant a lot to me."
Canada's next chance for a win is against Denmark on 28 December.
Overall, even though the Americans have won two out of the last six World Juniors (2010, 2013), Canada still retains the edge in this rivalry.
Canada’s record against the U.S. in World Junior play now stands at 33 wins, three ties, and eight losses. Dating back to 2005, Canada has won 11 out of its last 14 meetings with the Americans.