With just four weeks to go before Canadians choose their next prime minister, burgeoning Liberal support in Ontario has pushed party support past the NDP for the first time in the campaign, according to a new Ipsos poll conducted on behalf of Global News.

Approximately 33 per cent of Canadians prefer the Liberal Party, according to the poll – three percentage points ahead of the NDP, and six points ahead of the Conservatives.

It’s the first time since the campaign began that the NDP hasn’t been the most popular party. And the Liberals’ gains have largely been driven by growing support in Ontario, according to Darrell Bricker, CEO of Ipsos.

“Ontario… the most seats are up for grabs there,” Bricker said. “It’s critical that you’re doing well in that province, especially if you’re not doing well in other places.”

READ MORE: Undecided voters could be ‘decisive’ in this federal election, say experts

Bricker noted that the Liberals built their dynasty in the 1990s on Ontario, and to a lesser extent Quebec, and despite not doing well in the rest of the country, they were able to form government.

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And most of the Liberal gains over the last week have come at the expense of the NDP, not the Conservatives.

Liberals leads in Ontario, NDP leads in Quebec, Tories take Alberta

The Liberals enjoy 41 per cent support in Ontario, a sizeable lead over the Conservatives at 32 per cent and the NDP at 24 per cent. The Green Party has three per cent support. The Liberal Party also has a solid lead in Atlantic Canada with 49 per cent support.

“[Ontario] is the place where Thomas Mulcair really hasn’t broken through, the Liberals also hold on to a really strong lead in Atlantic Canada but as anyone who follows politics knows, there’s not a lot of seats in Atlantic Canada, you have to win in other places,” Bricker said.

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The NDP retains its dominance in Quebec with 37 per cent support, 14 percentage points more than the Liberals, 15 more than the Bloc Quebecois, and 24 more than the Conservatives.

The NDP has an eight-point lead in British Columbia with 36 per cent support, to the Conservatives’ 28 per cent, and the Liberals’ 24 per cent. The Green Party has 10 per cent support, their most in any province.

The Conservatives still dominate in Alberta with 39 per cent support, and Saskatchewan and Manitoba where they have 44 per cent support.

Nationally, the Liberals and NDP have switched places over the last seven days with the Liberals picking up two percentage points, while the NDP lost two. The Conservatives too lost two points since last week, according to the Ipsos poll. The Green Party and Bloc Quebecois, bring up the rear with four per cent and three per cent support, respectively.

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“[The Liberals] had a good week,” Bricker said.

But that doesn’t mean Trudeau has cemented his lead – far from it. The 42nd election campaign is the longest ever and, to use a cliché, more of a marathon than a sprint – and no one has pulled away.

“What it shows is that, it’s almost like watching runners in a long race. At one point one person gets at the front of the pack, everybody drafts off of them for a while, and then somebody else moves to the front of the pack. That’s what we have right now,” Bricker said.

“It looks like it is the Liberals’ week to lead the pack.” Tweet This

The desire for change remains strong with 71 per cent of respondents saying it’s “time for another federal party to take over” compared with just 29 per cent who say the “Harper government has done a good job and deserves re-election.”

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And who won the debate?

The Liberals’ bump in the polls follows Trudeau’s strong showing at the Globe and Mail debate on the economy last week. Most respondents to the Ipsos survey say Trudeau, despite lower expectations of him than the other two, won the debate.

WATCH: Watch all the highlights as Stephen Harper, Justin Trudeau and Tom Mulcair dropped the gloves in Thursday’s leaders debate.

Mulcair, Harper, Trudeau still neck and neck and neck on other metrics

Despite Trudeau’s strong showing at the debate, he’s failed to pull ahead in other key metrics – like which leader would make the best prime minister.

Mulcair still has a sizable lead over his two opponents in that key metric – 38 per cent see the NDP leader as the best candidate for prime minister. Thirty-two per cent say Trudeau, and 28 per cent say Harper.

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“But all three of them, just like they are in terms of party support, are pretty competitive on that question,” Bricker said. “A marathon is being run, the leaders switching from week to week, nobody is really breaking away from the pack.”

Similarly, Mulcair is seen as the candidate best able to deal with Canada’s shaky economy – though he is tied with Trudeau at 34 per cent.

“This is something that usually the Conservatives own,” Bricker said. “The big card that the Conservatives have to play is that they’re the best economic managers, if you throw that into question, then everything else kind of tends to fall apart.”

Harper, despite his insistence that Canadians should stay with the status quo, is ranked third with 31 per cent seeing him as the best leader to deal with the economy.

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-With files from Eric Sorensen

Exclusive Global News Ipsos polls are protected by copyright. The information and/or data may only be rebroadcast or republished with full and proper credit and attribution to “Global News Ipsos.” This poll was conducted between September 18 and September 21, with a sample of 1,103 Canadians from Ipsos’ online panel and is accurate to within 3.4 percentage points 19 times out of 20.

View the full Ipsos tables below: