The upcoming Battle of Ontario between the Toronto Maple Leafs and Ottawa Senators can be analyzed through many lenses, whether it’s historical context, opinion pieces, or just sheer provincialism, but we’re taking a different route in this piece: the easiest predictor of what may happen in this series stems from this year’s head-to-head matchups.

Ottawa swept the season series 3-0, providing Toronto with some much-needed lessons. We’re going to examine what went wrong tactically, and what we need to know about the Senators ahead of Sunday’s Game 1.

North-south hockey is a common refrain you’ve heard from the 2024-25 Maple Leafs, particularly from head coach Craig Berube, who wants the Maple Leafs to mitigate risks at all costs and get pucks to the net-front. As a result, the Maple Leafs haven’t always operated like a team that boasts some of the best offensive talents in the world at times, especially at 5-on-5, but they are finally hitting top form amid a 13-2-1 stretch run to close out the season.

You’ll often hear the adage ‘time and space’ when players discuss how to shut down stars, and the Senators seemingly understand this better than most. Ottawa flummoxed Toronto’s best players through the regular season and with standout defenceman Jake Sanderson leading the way, it facilitated easy exits. In effect, the Maple Leafs kept punting on one-and-done possessions by dumping the puck in, the Senators fished it out, and used their speed in transition to cause chaos.

This was clear particularly during the March 15 matchup, where the Maple Leafs’ frustrations — and perhaps my own! — were readily apparent.

Sanderson is truly a superior skater and it’s been the main factor during this year’s head-to-head matchups, where Toronto struggled to generate offence, while Berube often tested out line combinations to little avail: the Bobby McMann-John Tavares-Mitch Marner line was quickly abandoned after the March 15 game, while Matthew Knies-Auston Matthews-Max Domi was a combination that was worth experimenting with, but ultimately, it’s not a unit that the Leafs will use, even when it’s time to get creative while trailing.

Ottawa is an inferior team at 5-on-5 with 139 goals scored, the second-fewest in the NHL. Although Toronto is heavily favoured in this matchup due to superior talent, it can get flummoxed when forced to get creative inside the offensive zone. Senators head coach Travis Green has revamped his team’s commitment to team defence, and will do everything they can to get the Maple Leafs outside of their comfort zone, which effectively amounts to prioritizing high-danger shots over everything, as opposed to a volume-based, improvisational approach under Sheldon Keefe.

Here is a direct passage from my March 15 notebook:

This has been a commonality against the Senators. In a relatively low-event game on January 25, the Senators effectively suffocated the north-south approach. Here’s what my colleague Alex Hobson wrote in his post-game analysis:

North-south hockey has been the core tenet of Berube’s philosophy, and it will be put to the test against a Senators team that is better than the sum of their parts.

Toronto has become an excellent defensive team under Berube. We’ve already gone over the risk mitigation, but Chris Tanev, Jake McCabe, Brandon Carlo, Morgan Rielly, Oliver Ekman-Larsson have provided Toronto with its best five-man rotation over the past decade. Simon Benoit has strung together a series of excellent games over the past month, and it’ll be curious to see his form continues into the playoffs.

Rush defence has been a continued point of emphasis for the Maple Leafs, and I wrote about how the team struggled out throughout January containing teams in transition, with exemptions granted to Tanev and McCabe, the best point-of-attack defender on the team.

The possession battle has been pretty even through three contests, but the Senators punished the Maple Leafs for turnovers in each of their three games. Here’s an example where Rielly fumbles the puck in his defensive zone, the Maple Leafs get flummoxed trying to win back the puck, and David Perron scores, during the March 15 contest. Carlo has stabilized Rielly’s play throughout the past month, and perhaps there were some errors due to a lack of continuity, but the point remains that the Senators are going to punish the Leafs’ mistakes, while hoping for a low-event game.

Toronto has allowed the third-fewest goals at 5-on-5 this season, and the fewest allowed of any Eastern Conference team. It should be able to dominate possession, the quality of chances, but it simply cannot afford costly mistakes in the defensive end. We’ve written about Sanderson, the Senators’ most important player in this series — along with goaltender Linus Ullmark — and Ottawa’s ascending star defenceman has given the Maple Leafs’ fits by pinching from the offensive blue line to keep plays alive.

It’s not a stretch to suggest that William Nylander is the only member of the Maple Leafs’ vaunted Core Four that has played well against the Senators this year, as his game-breaking speed, opportunism and individual efforts always translated well. Berube often experimented with his lines against the divisional rival, but Nylander’s stellar play was one of the lone, few constants. And now it’s incumbent upon the Maple Leafs’ top-six to win their matchups handily.

Ottawa’s top line of Brady Tkachuk, Tim Stutzle and Claude Giroux dominated in the March 15 game, to the tune of a 7-2 shot differential at 5-on-5 and a 75 percent share of the expected goals. During 220 minutes and 44 games shared together in all situations, Tkachuk-Stutzle-Giroux have sported a minus-two differential. Advantage, Maple Leafs!

Toronto’s top line of Matthew Knies, Auston Matthews and Mitch Marner will be hounded by the Sanderson-Artem Zub defence pairing, but it ought to cook in this matchup. Marner is coming off a tour-de-force 102-point campaign, Knies has emerged as one of the NHL’s breakout stars, while Matthews is all the way back, shaking off the ill-effects of an undisclosed injury, which has affected his long-range shooting more than anything this season. And while there will be natural anxiety and consternation surrounding Toronto’s stars, who often shrink in the playoffs, Matthews and Nylander are both healthy entering this year’s series.

Berube’s experimentation hours are over, and the Knies-Matthews-Marner unit are Toronto’s second-most commonly used unit for the second consecutive year. If they cannot beat the Tkachuk line, they will be subject to a tremendous volume of criticism. This is the year for the Maple Leafs, and while Nylander’s ability to operate as a one-man shot-creation machine has been apparent in the first three matchups, Toronto’s top line and John Tavares (who has been arguably the team’s best player at 5-on-5 since the 4 Nations break) are due for an explosion.