Everyone knows the importance of special teams play and goaltending in the Stanley Cup playoffs.

With the league's parity at five-on-five, if one of those areas falters, a team is likely cooked.

Throughout the Senators' 2024-25 season, much has been made of their penalty kill unit and its reliance on its diamond structure. It has been a subject of debate all season long because of its wavering efficiency.

Most teams elect to run umbrella power plays with an attacking player quarterbacking the unit in the middle of the ice near the blue line.

The diamond structure intends to take away the front of the net and slot by stationing one defenceman at the top of the crease and a forward at the top of the circles or high slot. When it operates efficiently, it clogs up the middle of the ice, keeping the opposition to the periphery where fewer dangerous chances should exist - simultaneously putting pressure on the goaltender to make the save when he has clean looks at the shooter.

It can succeed when its units are aggressive and pressure the opposition, but each penalty killer has a responsibility to defend his area while anticipating where open space could occur and be ready to defend those passing lanes and space.

That aggressiveness is what head coach Travis Green has liked about his group of late.

"They're doing a good job being aggressive when they need to be," Green stated, explaining its recent string of efficiency. "It's been a work in progress all year. The more times we're aggressive, the better.

"It's done a good job for the last (while). I think we had one game where we got stung for a few, but for the last four to six weeks, it's been much improved."

Its improved success corroborate the head coach's observations.

Since March 8, the Senators' penalty kill has fared well.

In their last 20 games, the organization has successfully killed 82.6 percent of their penalties - the 11th-best rate in the league in this stretch of games. It is a marked improvement from their season's 77.9 percent success rate.

The penalty kill has been a polarizing point of discussion because, at its worst, it can be too passive and involve poor reads and switches. In several important instances, its passivity allowed the opposition to work the puck from high to low, creating two-on-ones that are difficult to defend, putting a ton of pressure on the goaltender to make high-danger saves.

The results in the early going, were not particularly impressive per NaturalStatTrick.

Through the team's first 61 games:

• 100.21 CA/60 (13th)
• 55.33 SA/60: (24th)
• 8.61 GA/60: (22nd)
• 8.27 xGA/60: (19th)

According to veteran defenceman Nick Jensen, there were some valid explanations for the slow start.

"There was a learning curve with the PK," Jensen said. "I think for a lot of guys, it was a new system for them. I know for me personally, throughout the year, it's been a little bit of a learning curve, but I think guys are starting to grasp it pretty well.

"Obviously, our first unit of penalty killers has been spending a significant amount of time out there, and I feel like they're starting to read off each other well because it's a unit of four out there that needs to work together in our system."

When asked to explain the most significant difference when the unit operates efficiently, Jensen attributed it to a natural progression where the players feel more comfortable making reads.

"It's just the intricacies of our kill," the defenceman said. "There are a lot switches and reads that you have to make. The quicker we can make those reads, the better our PK will be, and it's harder for the power play to get those scoring opportunities."

Looking at the Senators' penalty kill numbers, the rate at which they have given up shots and chances has actually increased since March 8.

• 117.12 CA/60 (29th)
• 62.22 SA/60 (30th)
• 5.86 GA/60 (11th)
• 9.98 xGA/60 (30th)

Across all of the metrics, whether it is the rate of shots allowed or expected goals allowed, the Senators are allowing higher rates than they were earlier in the season.

So, what is the principle reason for the improvement?

Veteran forward Claude Giroux had the answer.

"We're trying to be aggressive when it's time to be aggressive and goaltending has been great for our PK," he admitted. "Anytime everybody's on the same page, just makes a lot of everybody's job a lot easier."

Getting saves can mask some problems, and as HockeyViz's data shows, the Senators have given up an extremely high rate of shots in high-danger areas.

The cerebral Linus Ullmark had an excellent explanation of what it has been like to play behind this penalty kill structure.

"(The important thing) is knowing the tendencies and how people (behave) because everybody's different," Ullmark clarified. "Some forwards are really good at blocking shots. Some forwards are really explosive, going up and down and pressuring. Some people have very good sticks, and some are just in very good position.

"So, getting the tendencies of understanding where and when the shots are going to come from will get you in a position where you weren't prepared for the shots (before). That was also something that I had a very hard time with in the beginning because I couldn't tell, like, 'What are we doing? How are we doing it?'

"We had a lot of meetings, a lot of conversations, but then just at one point, I thought, 'Okay, just let it go. Just leave it be. Do your own thing and worry about yourself.'

"So, I started working more on what I could have improved and that has led to me understanding and knowing more about what I need to be doing at certain times, where the danger is going to come from, where the puck is going to be shot from. But, then you play a couple players who are pretty silky smooth as well, so you never know at the end of the day. But, it's definitely been a positive influence in our team's defence to kill off more penalties now than we did in the beginning of the season."

Since March 8, the Senators' goaltenders have stopped 90.59 percent of the shots on the penalty kill.

If Ullmark is at a point where he feels the predictive nature of the penalty kill allows him to get dialled in, and it better serves his anticipation, perhaps that is all that matters.

The Senators will be relying heavily upon him in the postseason and if they are to have a chance against the Toronto Maple Leafs, he will have to continue to stand on his head when his team is shorthanded. 

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