On a night when both sides of the Battle of Ontario wanted nothing more than a Game 1 win, Mitch Marner and the Toronto Maple Leafs were the ones to deliver.

The team’s leading scorer and biggest target for criticism regarding Leafs playoff failures alike, Marner showed up in a big way on Sunday to help his case for the latter. He scored a breakaway goal in the first period and added an assist on what was a multi-point night for each member of the Core Four, helping his team to a 6-2 thumping of the Ottawa Senators in Game 1.

Marner takes a lot of heat for his lack of production in big games, particularly later in the series, but the question has never been about his desire to win or his effort level. A lot of the time, it comes down to the mental game, and being able to set aside any demons or expectations when the puck drops goes a long way. He proved that he was capable of magic in big games at the 4 Nations Face-Off, scoring an overtime game-winner against Team Sweden in the round robin, and assisting on Connor McDavid’s tournament-winning goal against the United States. Marner noted that this experience has been a primary contributor to settling his game down in these big moments.

“Maybe just a sense of calmness, confidence,” Marner said when asked what playing those 4 Nations games did for his game in the NHL. “That tournament was pretty quick, obviously very intense, and that’s kind of what playoffs is. It kind of happens quickly, games go by fast and you have to look forward to the next one and realize that it’s going to be even harder. So, just calmness and confidence from that tournament, which helps.”

Marner assisted on the first of three power play goals for the Leafs, and said that executing fast plays was a big reason why they struck with the man advantage.

“I think just our quick plays off the draws,” Marner said. “Willy [Nylander] walking off there that one, finding John [Tavares] for that high tip as well, and then Kniesy [Matthew Knies] making a great tip play on my shot that Auston kind of bumped back towards him.”

Although stressful for fans of the team in the moment, the first game of the Battle of Ontario had everything anybody could have asked for. Lots of goals, a ton of physicality, and some end-of-game theatrics.

“I think just like everyone talked about, it was intense,” Marner said of his first playoff Battle of Ontario experience. “You knew it was going to be a fiery series, and that’s what tonight showed. I thought we did a good job of just staying calm in the moment, and when we had our looks, we made good on them.”

The Leafs have to feel good about the way they played, but they’re not satisfied with it nor should they be. They have a good chance to take this series, but will be treating each game like it’s their last, and as Marner knows better than anybody at this point, there’s no other mindset to have in the playoffs.

“It was a good start, we need to keep building and finding ways to get better.”