How winning the 'slot battle' has driven the Bruins' run to the Stanley Cup Final

May 12, 2019; Boston, MA: Boston Bruins left wing Jake DeBrusk shoots on Carolina Hurricanes goaltender Petr Mrazek during the first period in Game 2 of the Eastern Conference Final of the 2019 Stanley Cup Playoffs at TD Garden. (Greg M. Cooper-USA TODAY Sports)
May 12, 2019; Boston, MA: Boston Bruins left wing Jake DeBrusk shoots on Carolina Hurricanes goaltender Petr Mrazek during the first period in Game 2 of the Eastern Conference Final of the 2019 Stanley Cup Playoffs at TD Garden. (Greg M. Cooper-USA TODAY Sports)

By Matt Dolloff, 985TheSportsHub.com

The Bruins have looked like a much better team in the 2019 playoffs, as compared to 2018. It's due in large part to their performance in the slot.

Sounds simple enough. Get to the fabled "scoring area" between your opponent's faceoff circles more than they get to yours, and you'll succeed. To be sure, there are advanced analytics that back that up. Those stats helped Bruce Cassidy map out the Bruins' improvement in the postseason - and proof that they've made a leap forward in slot play is in the numbers, your eyeballs, and the scoreboard.

Speaking as part of his approach to analytics, Cassidy told reporters after Monday's practice that he has placed a major emphasis on playing better in the slot than the other team. He got the Bruins rolling in that department thanks to a tip-off from advanced statistics.

"I do believe that teams that control the slot battle - and I think that’s eye test, too, but the numbers really back that up - win the majority of the games," Cassidy said. "I think for me, it’s you keep them out of the prime scoring area, you get to the prime scoring area. That’s a big determiner. So we constantly look at that area."

Chris Wagner of the Boston Bruins scores a goal on Curtis McElhinney of the Carolina Hurricanes during the second period in Game 3 of the Eastern Conference Finals during the 2019 NHL Stanley Cup Playoffs at PNC Arena on May 14, 2019 in Raleigh, North Carolina. (Photo by Grant Halverson/Getty Images)
Chris Wagner of the Boston Bruins scores a goal on Curtis McElhinney of the Carolina Hurricanes during the second period in Game 3 of the Eastern Conference Finals during the 2019 NHL Stanley Cup Playoffs at PNC Arena on May 14, 2019 in Raleigh, North Carolina. (Photo by Grant Halverson/Getty Images)

Cassidy also pointed to assistant coach Jay Pandolfo's focus on increasing "rebound chances". They have spent added time coaching the Bruins up to get more of those and allow less. The Bruins have enjoyed more time and opportunities in the slot than last spring, and the difference is stark.

"That’s going back to Jay, because he was harping on that, the rebound chances. Because that means you’re getting inside. I guess that’s the term, right? Getting inside," Cassidy continued. "We had trouble last year with Tampa. This year we’ve been better. I thought we did a good job against Carolina keeping them to the outside ... I do believe it’s one of the reasons we didn’t give up a ton of goals."

As you'd expect, the data backs up Cassidy's claims. You can see the difference at analytics database Natural Stat Trick, which keeps track of slot play with "high-danger" scoring chances.

In their five-game defeat to the Lightning a year ago, the Bruins lost the 5-on-5 high-danger chance battle by a 38-25 margin (just 39.7 percent for Boston). Through 17 games this year, the Bruins have out-chanced their opponents in the danger area 150-130 (53.4 percent). They're 8-0 in games where they get more high-danger chances, compared to 3-4 when they lose the battle and 1-1 when they tie it.

As Cassidy also made sure to note, Tuukka Rask is another major reason the Bruins have limited the opposition in the danger areas. Game 4 of the first round against the Toronto Maple Leafs is a major outlier. The Bruins won that game 6-4, despite the Leafs out-chancing them in the high-danger area 14-7 (all situations). Rask stopped 38-of-42 Toronto shots (.905 save percentage) in all, compared to just 25-of-30 for Frederik Andersen (.833). So even when the Bruins are faltering in the slot battle, their goaltender has been there to bail them out.

Cassidy explained how he uses analytics in great detail during Monday's presser. But to distill it down to a paragraph, he uses certain key data points to identify areas of improvement. Then he coaches accordingly. Analytics may be a small part of Cassidy's overall coaching process, as compared to practice and execution. But apparently, it has played a significant role in his big-picture decisions.

Tuukka Rask of the Boston Bruins makes a save against the Carolina Hurricanes during the first period in Game 3 of the Eastern Conference Finals during the 2019 NHL Stanley Cup Playoffs at PNC Arena on May 14, 2019 in Raleigh, North Carolina. (Photo by Grant Halverson/Getty Images)
Tuukka Rask of the Boston Bruins makes a save against the Carolina Hurricanes during the first period in Game 3 of the Eastern Conference Finals during the 2019 NHL Stanley Cup Playoffs at PNC Arena on May 14, 2019 in Raleigh, North Carolina. (Photo by Grant Halverson/Getty Images)

Cassidy's approach to the "slot battle" has obviously paid dividends on the ice and in the win column. But it's also been the right approach to keep his coaching to coaching. His players don't want to relive their calculus teachers.

"I like the data, but I'm never going to go into the locker room one day and say 'We had 16 controlled entries last game'," Cassidy remarked. "I don’t think the players give a crap about those raw numbers. That's more for us, backing up what we’re teaching, and how we’re executing."

The Bruins coaching staff and the numbers have worked in concert to deliver a better on-ice product - especially at the defensive end. Protecting the front of their own net is just as important as crashing the opponents' on offense. Against the obviously inferior Carolina Hurricanes, the Bruins anticipated rushes well and used positioning to force the majority of their chances outside the slot area. The Game 4 clincher was an absolute clinic on how to keep your opponent away from your net.

If you've been watching this Bruins team and seen a more efficient, controlled defense around the net - and a more aggressive, opportunistic offense - it's not a mirage. Cassidy made it a point to improve the team in the slot. And while it ultimately comes down to the staff's instruction and the players' buy-in, Cassidy credited a simple advanced stat for steering the Bruins in that direction.

That kind of balance between data and good-old-fashioned coaching has the Bruins in position to win another Stanley Cup. And based on how they've performed in the slot at both ends this spring, they should finish the job.

Matt Dolloff is a digital producer for 985TheSportsHub.com. Any opinions expressed do not necessarily reflect those of 98.5 The Sports Hub, Beasley Media Group, or any subsidiaries. Have a news tip, question, or comment for Matt? Follow him on Twitter @mattdolloff or email him at [email protected].