The stakes were high in a close three-party race, but no one leader set themselves apart from the rest of the pack. Still, the debate revealed a few important details.

Here are five points to take away from the first leaders' debate of the 2015 election campaign.

1. Stephen Harper can be shaken

If Conservative Leader Stephen Harper needed to look prime ministerial and remind people why they elected him the last time around, he seemed to deliver a mostly steady performance. But not entirely.

Harper is generally unflappable in public but this debate showed a couple of cracks in his rhetorical shield: Harper can be shaken, even on questions about the economy.

Tom Mulcair presses Justin Trudeau on what the Liberals' deciding number would be in a referendum on Quebec’s sovereignty 1:11

The Conservatives want the election to be about economic management and national security, traditional strengths for the Conservatives. But in one exchange, Harper admitted the Canadian economy is on the verge of a recession after it shrank for five straight months. One more month, to close out two quarters, meets the definition of a recession.

​Harper also got flustered during the debate section on the Senate, telling the other leaders that Conservative senators vote as they're told by his office, rather than based on what the senators think of legislation.

Senators used to ‎vote less along partisan lines but have in recent years closely mirrored their colleagues in the House.

"We cannot force them to do anything... but we ask them to support the party's position," Harper said.

2. Fighting for the left

For NDP Leader Tom Mulcair and Liberal Leader Justin Trudeau, it would have been important to look stable enough to replace Harper, but different enough to appeal to voters wanting a change. And different enough from each other to look like the best choice for voters seeking a change in government.

Liberal Leader Justin Trudeau, Green Party Leader Elizabeth May, NDP Leader Tom Mulcair and Conservative Leader Stephen Harper clashed over their political priorities in Thursday's debate. (Mark Blinch/Pool/Canadian Press)

Trudeau and Mulcair, who have different visions but are still competing for many of the same voters, spent almost as much time contrasting their policies with each other as they did contrasting them with Harper's.

It led to some notable exchanges, particularly on pipelines when Harper could stand back and watch Trudeau and Mulcair discuss who had the most confusing positions and which leader had said one thing in French and a different thing in English.

3. May held her own

Green Party Leader Elizabeth May's task was to make sure she made an impression during the debate rather than letting the other leaders leave her out, and to remind people the party isn't a one-issue organization.

Tom Mulcair presses Stephen Harper on Canada's shrinking economy for the past five months 0:28

May avoided being sidelined and brought some important context on issues she's been vocal about — including C-51, which gave more power to Canada's spy agency, CSIS, and the environment.

In particular, she made clear that Mulcair hasn't taken a position on a Kinder Morgan pipeline expansion in Vancouver, forcing him into a series of non-answers during the debate on energy and the environment.

4. Trudeau got in his jabs

Expectations might have been lowest for Trudeau going into the debate, despite his rival's assertion to the contrary. But with his party in third, there was a lot to gain with a strong performance.

While he had some feisty exchanges with Harper, Trudeau also seemed nervous at times and stumbled badly in his closing, sounding stiff and rehearsed before going over his time.

Liberal leader Justin Trudeau speaks during the Maclean's National Leaders debate in Toronto. (Mark Blinch/The Canadian Press)

That said, he probably had the most memorable exchange of the evening with Mulcair in the debate over Quebec sovereignty. Mulcair, whose NDP would let Quebec separate from Canada in the case of a clear 50 per cent plus one vote in favour, was pushing Trudeau for his own number.

"You're not answering...you haven't answered," Mulcair pressed.

"You want a number? I'll give you a number. My number is nine," Trudeau said, referring to a Supreme Court decision which he says contradicts Mulcair's policy.

5. Mulcair strong on the offensive

On the offensive, Mulcair was strong against Harper and Trudeau, forcing Harper into admitting Canada is very nearly in a recession, and generally keeping his opponents on their guard.

Elizabeth May says carbon emissions have risen under Conservative rule 1:01

Mulcair's built a reputation as a tough questioner in the House, but the party has spent a lot of time softening his image, emphasizing his role as a father, son and brother, and putting him in photo ops with animals.

In Thursday's debate, this seemed to manifest itself through a continuous smile on his face. In the end though, forced smile or not, Mulcair's experience in the House served him in the more heated exchanges as he tried to pick at Harper's record and plug his own plans.