When they played O Canada for the second time, there were no American fans left in their own arena to boo.

Instead, after a tense game that began with the Boston crowd jeering the visitors’ national anthem, it was the Canadian team that stood arm in arm wearing their championship hats while the maple leaf flag was lowered behind the 4 Nations Face-Off trophy and the national anthem reverberated across the Americans’ home ice. The fans who remained, many of them in their red Team Canada jerseys, sang along.

Connor McDavid scored at 8:18 of overtime to give Canada a 3-2 victory over the United States on Thursday night as the North American rivals turned what had been a tune-up for the 2026 Olympics into a geopolitical brawl over anthems and annexation as much as international hockey supremacy. Or, to put it another way: It was the 51st US state 3, Canada’s 11th province 2.

“You can’t take our country – and you can’t take our game,” Canadian prime minister Justin Trudeau posted on X after the game, in a cross-border callback to US president Donald Trump’s chatter about annexing one of the United States’ closest allies.

Earlier this week, USA Hockey general manager Bill Guerin told Fox News that the team “would love it if President Trump was in attendance” at the final. Trump declined, but on Thursday morning on Truth Social he said he would call the US hockey team “to spur them towards victory tonight against Canada, which with FAR LOWER TAXES AND MUCH STRONGER security will someday, maybe soon, become our cherished, and very important, Fifty First State”.

Ever since Trump began threatening to impose crippling tariffs on Canada – its closest ally and biggest trading partner – coupled with threats to annex it, Canadians have responded with an unusual level of patriotism. One pilot flew his small plane in the shape of a maple leaf; consumers have pledged to buy only Canadian-made products; and sales of Maga-style hats reading “Canada is not for sale” have skyrocketed.

The resentment seemed to spill over into the Four Nations competition, which took the place of the NHL’s usual All-Star game and also featured teams from Sweden and Finland. When Canada and the US met for their first match last Saturday, there were three fights in the opening nine seconds.

Thursday’s thrilling rematch proved that Trump’s geopolitical intervention was a much more unpredictable and meaningful surprise than any marketing gimmick the league could have dreamed of.

“A lot of stuff going on with Canada and the USA right now, and us playing against each other was kind of a perfect storm for our sport,” said Nathan MacKinnon, who was selected the MVP of the new tournament with four goals in four games. “It was much more popular than even we would have imagined. It was getting so much attention from our whole continent.”

The game began with another political statement, when singer Chantal Kreviazuk modified the Canadian national anthem – intentionally singing “that only us command” instead of “in all of us command”, confirming after the game through a representative that it referred to Trump’s threats. On Instagram later she posted the new lyrics and wrote, “We should express our outrage in the face of any abuses of power.”

American fans responded with patriotism of their own, chanting “U-S-A! U-S-A!” regularly. In the third period, a chant went up for “Johnny Hockey”, the Boston College and Calgary Flames star Johnny Gaudreau, who was killed by a drunk driver while bicycling in New Jersey at his sister’s wedding last summer.

But the stakes for Canada seemed higher, perhaps reflective of an inherently unbalanced relationship that for two centuries or so has seen the smaller of the two partners defending itself. Hockey has been one of Canada’s few enduring emblems of supremacy – evidence it can present to the world at regular intervals to prove that it has not yet been totally subsumed, culturally or politically.

“I know it’s just a quick tournament, and it’s not an Olympic gold medal or anything like that, but it means the world to our group, as you can see,” McDavid said after the game.

“You’ve got 40 million Canadians, sitting at home, and you feel the energy,” Canada forward Mark Stone said. “We wanted this one.”

The feeling was perhaps intensified when, after the first game’s three fights in the first nine seconds, American forwards admitted they had planned in a group chat before the game to ambush the Canadian players.

When Canada’s Brandon Hagel was informed, he said: “I did it for the flag, and not the cameras,” referring to his fight with Matthew Tkachuk. “That’s a part of Canada that we have in there. We don’t need to initiate anything.”