Pros
The Leafs did many things right in game one, and that's why they won. Here is a closer look at all the pros from their Game 1 victory.
Discipline
One of the main things that got addressed before the series began was discipline, and the need for the Leafs to stay out of the penalty box. The Leafs received 18 minutes in penalties compared to the Senators 38 minutes. This resulted in the Leafs having six power plays and the Senators only having two. Although scrums after the whistle are commonplace in the playoffs, I think the Leafs need to be better at how they respond. The Leafs could have had a few more power plays if they didn't give in to the Senators' post-whistle antics.
Power Play
Speaking of the Leafs power play, it clicked for three of the Leafs six goals. The Leafs went 3-for-6 (50%) in game one, and that is exactly what fans want to see. It's important to capitalize on the other team's mistakes. If the Senators want to continue taking penalties, the Leafs need to continue making them pay for it by scoring on the power play.
Penalty Kill
The Leafs were perfect on the penalty kill. They did a good job of keeping the Senators to the outside and did not allow too many dangerous scoring chances. The end result was the Senators going 0-for-2 on the power play. Another factor in the Leafs good penalty kill brings me to the next pro from game one, and that's shot blocking.
Blocked Shots
Blocking shots is a painful yet necessary part of winning hockey games. The Leafs blocked 18 shots compared to the Senators; 12 in Game 1. Leafs forward Matthew Knies had one of the game's biggest blocked shots in the third period on a point shot from Tomas Chabot. The more shots being blocked means fewer pucks getting to the net, which makes the goaltender's job easier.
Star Players Showed Up
One thing the Leafs have been criticized for the most in years past is that the stars don't show up in the playoffs. Each member of the Leafs core four had a multi-point game in game one. Mitch Marner led the way with a goal and two assists for three points. William Nylander and John Tavares each had a goal and an assist for two points each, and team captain Auston Matthews registered two assists.
Defense Contributing
The Leafs did not receive much offense from their defensemen during the regular season. However, the defense Corp came up big in game one. Oliver Ekman-Larsson scored the game's first goal to give the Leafs the lead. In the third period, Morgan Rielly scored 45 seconds after the Senators made the game a 4-2 to give the Leafs a 5-2 lead.
Goaltending
Anthony Stolarz had an outstanding game for his first career playoff win. He finished the game with a 2.00 GAA and a .939 SV%, after making 31 saves on 33 shots. The Leafs will need him to play like he did in game one for the rest of the series and the playoffs.