While the American fans lightly booed “O Canada” on Thursday night at the 4 Nations Face-Off hockey tournament, the Canadian singer ad libbed new lyrics as a response to President Donald Trump’s chatter about turning the country into the 51st U.S. state.

A smattering of jeers for “O Canada” were eventually drowned out by the fans singing along with Chantal Kreviazuk, who changed the first verse from “true patriot love, in all of us command,” to “in true patriot love that none but us command.” The Canadian chart-topper posted a picture on Instagram of the phrase “that only us command” written on her left hand with emojis of a Canadian flag and a flexed muscle.

Publicist Adam Gonshor confirmed in an email to The Associated Press that Kreviazuk made the change as a rebuke to Trump.

“The Star-Spangled Banner” followed, with the sellout TD Garden crowd at full volume in an anthem battle that became the undercard for one of the most anticipated hockey games in decades.

Olympic hockey hero Mike Eruzione was greeted with “U-S-A! U-S-A!” chants when he took the ice during the pregame ceremony wearing a jersey of American star Jonny Gaudreau, who died in a bicycle accident last summer. The honorary U.S. captain shook hands with his Canadian counterpart, Hall of Famer Wayne Gretzky, in a sign of sportsmanship players and fans hoped would carry over to the game.

Among those taking an interest was Trump, who called the U.S. team in the morning to wish players good luck. USA Hockey posted a photo on social media showing general manager Bill Guerin standing in the middle of the locker room holding up a phone.

“It was so awesome to get his support,” U.S. center J.T. Miller said. “It’s a pretty big deal for him to take time out of his schedule to talk to us for five minutes. It’s just another one of those things where we’re kind of pinching ourselves this tournament.”

The rivalry between the North American hockey powers — already enough to get the attention of players and fans — has intensified after Trump threatened a tariff war and expressed a wish to make Canada the 51st U.S. state.

Trump posted on Truth Social on Thursday that he would be watching, and White House press secretary Karoline Leavitt said the president would be “watching for the United States to win.”

“And we look forward to the United States beating our soon-to-be 51st state, Canada,” she said.

In a post that referred to Canadian Prime Minister Justin Trudeau as “Governor Trudeau,” Trump invited the country to join the union. Trudeau has said that will never happen, and Canadian Public Safety Minister David McGuinty said during a news conference in Vancouver: “Sounds like President Trump is worried about the outcome of the hockey game tonight.”

“Canada is a sovereign and independent country. It has been for over 150 years and will remain so,” McGuinty said. “This discussion of 51st state is a non-starter.”

Guerin said on Fox News earlier this week the U.S. team would welcome Trump at the final. Trump had a prior commitment, speaking at the Republican Governors Association Meeting in Washington.

In spite of the political drama — or perhaps because of it — the tournament that returned NHL stars to international play after missing the last two Winter Olympics has delivered hockey of a quality that has conjured memories of some of the iconic games in history, including the American “Miracle on Ice” victory over the Soviet Union in the middle of the Cold War.

The Montreal fans loudly booed “The Star-Spangled Banner” last week during the round robin stage, when the North Americans had three fights in the first nine seconds in a game the U.S. won 3-1. The American fans responded — though less volubly — when the tournament shifted to Boston on Monday, as both sides have tried to lower the geopolitical temperature and focus on hockey.

USA and Canada sweaters intermingled with the usual Boston Bruins jerseys in the building lobby in the hours before the game as fans fist-bumped their countrymen while waiting in line for souvenirs or get into the arena.

Outside the stadium, a fan held up a sign saying “Welcome to the U.S.A. Canada’s 11th Province.” But most fans in Boston said they hoped the anthem booing and other bad feelings would not recur.

“I think everyone’s really here to watch the hockey game and I hope that’s really everyone’s motive,” said John Bennett, a Bruins fan from nearby Wakefield, Massachusetts, who was wearing a replica Eruzione jersey from the 1980 Olympics. “Because, at the end of the day, it is just a hockey game.”

Jason Brown, who was wearing a replica Wayne Gretzky Canada jersey and a Canadian flag as a cape, drove down from Victoriaville, halfway between Montreal and Quebec City, with his friends; one had an open Labatt beer handy as he tried to start a “Let’s go, Canada!” chant in the train station.

Asked about the politics, he said, “We don’t care about that. It’s all about hockey.”