TERREBONNE — Liberal candidate Tatiana Auguste won the Terrebonne riding north of Montreal for the second time in a year Monday after her one-vote victory in 2025 was overturned by the courts.

With all ballots counted, she led with 48.4 per cent of the vote compared to 46.8 for Bloc Québécois candidate Nathalie Sinclair-Desgagné, securing a clean sweep in the evening’s three byelections for Prime Minister Mark Carney.

Elections Canada had declared Auguste the winner over Sinclair-Desgagné by a single vote following the April 28 federal election last year.

Sinclair-Desgagné challenged the results after a supporter complained that she had tried to vote by mail using a special ballot that was never counted.

The Supreme Court of Canada invalidated last year’s result in a February ruling to set up a rematch.

Liberal candidates also won byelections in two Toronto ridings, giving the Liberals 174 seats and a majority in the House of Commons.

While the ridings were considered Liberal safe seats, Terrebonne — a former Bloc stronghold — was the biggest question mark of the night.

Auguste was mobbed by supporters and reporters as she made her entrance a few moments after TV networks declared her the winner.

“For me, the difference in this campaign was that people know me now. I was their MP for nine months and they know what kind of person I am and how I work,” she said after her win.

Earlier, preliminary results suggested another tight race, with the lead flipping back and forth between the two candidates. In a flashback to the last election result, each of the two top candidates was leading by one vote.

What began as a calm evening at a Liberal gathering at a Terrebonne restaurant grew increasingly more raucous as Auguste pulled ahead and held the lead, albeit a narrow one that grew and shrank.

It was a different story at Bloc headquarters, where a high-energy crowd kicked off the night waving flags and singing along to Quebec folk songs. By 11 p.m., the crowd thinned as Auguste’s lead grew.

After congratulating her opponents, Sinclair-Desgagné said her campaign would have needed a platform three times the size they had, a parade of ministers and a congress at Terrebonne’s front door to compete with what the Liberals brought.

“And despite all that, they beat us by just a few hundred votes,” she said. “It took a separatist to teach the rest of Canada a lesson in democracy.”

The Liberals pulled out all the stops to hold on to the riding in Quebec, even as it became increasingly likely the party would win a majority without it.

On Monday, Carney congratulated Auguste on social media.

“As a community builder and champion of the French language and culture, I’m pleased that Tatiana will keep working with our new government to build Québec strong and build Canada strong for all,” he wrote.

The surprise floor crossing of Ontario MP Marilyn Gladu from the Conservatives to the Liberals a few days ago lowered the stakes in the Terrebonne race, since it was no longer the make-or-break contest for Carney to get a working majority.

Industry Minister Mélanie Joly said during early results that the riding remained important to the Liberals, even if it was no longer needed to secure a majority. “We don’t take anything for granted,” she said.

Joly noted that prior to last year, the Liberals had not held the seat since the 1980s, and it was considered a Bloc stronghold.

“The riding is changing as the demographics in Quebec are changing as well,” she said. “But we are also a party in favour of national unity, and so we want to send a clear message there too.”

Some 18,200 people, or nearly 20 per cent of registered voters, cast a ballot in early voting.

This report by The Canadian Press was first published April 13, 2026.

— With files from Erika Morris

Morgan Lowrie, The Canadian Press