Facing the untenable proposition of squandering a 3-0 series lead, the Toronto Maple Leafs’ vaunted Core Four understood the assignment and delivered the signature performance that was asked of them.

William Nylander, on his 29th birthday, perhaps understood this task better than anyone. It was Nylander who delivered the edict ‘good teams find their way out’ when the Maple Leafs were amid a three-game losing streak in January, and he delivered the calm, confident performance expected of the team’s stars during a pivotal Game 6 in unfriendly territory. Nylander scored two goals on a three-point night, led all Leafs with four shots, and operated as a constant chance creation machine. It paid dividends, and it benefited his primary linemates, as Max Pacioretty scored the series-winning goal, added a primary assist on Nylander’s first tally and threw a team-high seven hits in the winning effort. After a dominant performance in Game 6, Nylander essentially summed up the natural confidence the Leafs should have, after dispatching their provincial rival, with the reigning champs up next.

“I think we’re happy obviously being in the second round, but now our focus is Florida, so that’s where our minds are at. We’re going to have a good night tonight, enjoy the win and then focus on Florida,” Nylander said post-game.

Auston Matthews also understood the assignment. Matthews and Marner submitted brutal performances in Game 5, where they committed key blunders, and were on the ice for all four goals surrendered. It was a different story in Kanata, and after being subject to round-the-clock criticism from the Leafs’ media corps — ourselves included — Matthews delivered for the Leafs with an expertly placed change-up that fooled Linus Ullmark on the power play during the first period. Toronto’s captain was outstanding in all facets, winning board battles, while winning 73 percent of his faceoffs. Matthews is paid to score goals, and while the Senators clawed their way back into the contest, the all-important first goal provided the Leafs with further confidence, in a signature game.

“We came into this game, a lot of noise on the outside,” Matthews said post-game to Sportsnet’s Kyle Bukauskas. “Just the belief in this group, in the room. The belief in one another to go out there and just play, shift-by-shift. Proud of the guys. That’s one step. Big game tonight, and we keep moving forward.”

Marner was excellent on the penalty kill and was at his best as a playmaker. He almost scored a terrific goal off a spin-o-rama, which drew the ire of some cynics, but he was physically engaged, and he finished with a primary assist. Marner is a pending free agent and he’s essentially betting on himself with the ostensible goal of becoming the highest-paid winger in the NHL. At least for one night, this is moot, as Marner finished the series with a goal and eight points in six games, while providing excellent all-around impact. And now, he’ll be tested against two of the game’s best two-way forwards in Aleksander Barkov and Sam Reinhart. He was facing all the pressure from the largest hockey market in the world and coming off the best regular season of his career, he was a key part of the closeout victory.

As for Tavares, it wasn’t a standout night, but he did hit the post and continued to use his size well to get to the net-front. Tavares was on the ice for three of the Leafs’ four goals and finished the game with a 69 percent share of the expected goals in all situations. He continued to bring out the best in Pacioretty and Nylander, and for a few shifts, Bobby McMann. The Core Four era started in earnest when Tavares signed a seven-year pact with the Maple Leafs on Canada Day 2018, and now on the final year of his existing deal, he’s turned back the clock in a renaissance year, while feasting in the slot. This iteration of the Leafs wouldn’t come together without Tavares, and now they’re off to the second round against the toughest opponent they’ve ever faced.

The Core Four were asked — demanded, if we’re being totally honest — to deliver a signature game in a hostile environment to close out the Battle of Ontario. They won the battle, and they won the war, against a cagey Senators team that forced the Leafs to win on the outside. It wasn’t always pretty and at times, the series appeared to be heading towards an ugly path, but Nylander, Matthews and the Core Four put their stamp on the series when it was called for. And for their next act, they’ll have prove themselves worthy of unseating the champions.