This time last summer, as Justin Trudeau rode a crest of public approval, you could imagine the Liberal leader living up to the hype—spreading energy and optimism across a political landscape scorched by negativity. He’d won some credibility as a riding-level campaigner. He’d pressed down the instinctive whimsy that made him look frivolous. He was a leader around whom his humbled party might coalesce.

But Prime Minister Justin Trudeau? The idea still required a certain suspension of disbelief. The inevitable barrage of Conservative attack ads would form an acid test of his leadership. (Would the Liberals fight fire with fire?) An even greater challenge lay ahead in Trudeau’s first campaign debate. His capacity to stand face-to-appraising-face with the battle-hardened Stephen Harper—to withstand and counter the PM’s cool dissections of Grit policy and Trudeau’s own public remarks—could determine whether the Tories’ just-not-ready branding would stick. Would he break out of the frame? Or would he play the part written for him, quailing before Harper’s intellectual might?

On Thursday, Trudeau came ready to fight. If you had doubts, he knocked them aside with a clangingly obvious morning photo-op, strapping on the gloves at a boxing gym and throwing a few combos at his trainer’s punch pads. More than a nod to his last great upset, a TKO win in a charity boxing match against Sen. Patrick Brazeau, it reflected the do-or-die nature of Trudeau’s challenge. If he landed even a few punches, he could compete with NDP Leader Thomas Mulcair for status as the presumptive alternative to the incumbent. If he confirmed the worst misgivings planted by the ads, he’d create a rut well nigh impossible to escape for the rest of the campaign. And, in this election, the Liberals’ share of the centre-left vote will be pivotal, possibly determining which party forms a government, and whether it wins a majority.

Score it, then, as a decision for Trudeau—if only because it wasn’t a decisive loss.

Kory Teneycke, the Conservative campaign spokesman, boasted before the Maclean’s debate that the Liberal leader would exceed expectations, “if he comes on stage with his pants on,” neatly summing up how deeply the Tories have distorted public perceptions of Trudeau with their ads. The trouble with that strategy is the damage to the messenger’s credibility when the story proves wrong, and Trudeau simply refused to play to type. Through all but a couple of exchanges, he maintained his poise, and although his handle on policy wasn’t as steady as Harper’s or Mulcair’s, it wasn’t glaringly weak. For two solid hours, he went toe-to-toe with three seasoned leaders. At no point did he seem out of place.

Trudeau’s best moments emerged from tilts at Harper. During an early exchange about economy and jobs, he took the PM to task over income-splitting and child-tax policies that benefit the wealthy, demanding that Harper “stop sending cheques to millionaires.” Trudeau then deftly turned a segment on international security and terrorism into a righteous oration on the Harper government’s “nickel-and-diming” of veterans, adding: “This government, which likes to wrap itself in the flag, is actually not caring for those people who have fought, injured themselves and, in many cases, died.”

Most surprising was the 43-year-old’s recovery from attacks—not least NDP Leader Tom Mulcair’s attempts to pin him down on the threshold for Quebec separation. Trudeau had walked into the snare, pivoting from a question on electoral reform to criticize the New Democrat promise to respect a referendum vote to separate of 50 per cent plus one ballot. Wearing a Cheshire-cat smile, Mulcair turned to his Liberal opponent, and repeatedly demanded: “What is your number, Mr. Trudeau?”

Evidently, Trudeau saw the move coming. “My number is nine,” he countered. “Nine Supreme Court justices said one vote is not enough to break up this country. And yet that is Mr. Mulcair’s position.”

That parry, referring to the Supreme Court of Canada opinion on the Clarity Act, was one of several in which Trudeau spun away from imminent harm, including an effective shading of the Liberals’ support for anti-terror legislation widely criticized as a threat to civil liberties and constitutional rights. Instead of defending Bill C-51, he claimed credit for improving it through much-needed amendments at the committee stage, noting that the Liberals are committed to repealing elements of the bill that experts have identified as constitutionally problematic.

It was by no means a perfect performance. Trudeau struggled to insert himself into some exchanges, and he served up a couple of awkward verbal constructions, (Harper, he complained, has failed to convince Canadians “of the rightness of his pipelines.”) But his confidence combined effectively with his warmth on camera to create a sense of competence, compassion and sincerity. Of all four leaders, including the Green party’s Elizabeth May, he seemed the most human.

For his opponents, that’s a problem, undoing their best-case scenarios and changing the game from this point forward. A Trudeau implosion would have set Mulcair up as the only alternative to Harper, lifting him from the mid-30s in popular vote to majority territory. The Conservatives, meanwhile, hoped for a Trudeau who performed only well enough to split the anti-Conservative vote, sending Harper on a path to a second majority. If Thursday’s glimpse is anything to go by, neither is a certainty.