BOSTON -- After what the team deemed an "ugly" win on Thursday, the Boston Bruins (3-0-0) came out and exerted total control over the Buffalo Sabres (0-2-0), setting the tone for an eventual 3-1 victory on Saturday night inside TD Garden.

The Bruins put together their best performance of the season on Saturday night. Mark Kastelic, in particular, stood out in the Boston victory. He scored his first of the year and buzzed up and down the ice.

Notably, the Bruins' penalty kill was perfect for a third game, 3/3 tonight to move the kill to 12/12 on the season.

"I think just everybody's on the same page," said Kastelic of the penalty kill. "One and two, we're just on our toes, and we're aggressive. Nobody's sitting back; everybody's competing, and everybody's taking a lot of pride in that on the PK. Which, I think, is the biggest thing. So, that's what I'd probably go with."

"I think their intensity," said Jeremy Swayman, when asked why the kill has been perfect to start the season. "It's our four outwork their five, and it's obvious. That's something that we all can get behind and stick to within our identity. I know it's just a huge momentum shift for us when we get kills like that.

I'm just so happy with the guy's effort and attention to detail, sticks and lanes, and obviously blocking shots and good communication."

Swayman himself played well yet again, turning aside 21 shots in the victory. He only faced two shots in the first period, then had to deny multiple onslaughts of Buffalo pressure.

Bruins' Head Coach Marco Sturm called Swayman the Bruins' best killer, and praised the unit as a whole postgame. He also remarked it was Boston's best start to a game in the regular and preseason, something he's been urging the Bruins to get better at.

Right from the jump, Boston put their foot on the throat of a team decidedly inferior, outshooting Buffalo 17-2 in the first 20 minutes.

Even so, Boston only found one goal in the first 20 minutes, courtesy of Pavel Zacha.

The goal, firstly, is an unbelievable shot by Zacha. Just a total howitzer from the Czechian. But, that play doesn't happen without the unbelievable pinch and feed from Jordan Harris.

Harris, a native of nearby Haverhill, Massachusetts, made his Bruins debut and accentuated that with the gorgeous assist. The awareness and quick step to get to the loose puck allowed Boston's forwards to slide into position to receive a pass, especially Zacha.

When the second period began, Boston had to weather an early storm from the Sabres, desperate to show any signs of life. Boston weathered it, even killing a pair of penalties early in the second.

Boston's power play received some chances too and despite good puck movement and chance creation, could not buy one on their first four attempts in the first 40 minutes. 

However, the momentum generated directly led to Kastelic's goal. Less than a minute after a man advantage expired, the fourth line went to work.

Kastelic just throws it toward the net, and it takes a lucky bounce. Sean Kuraly set a nice moving screen as well, contributing to the chaos.

As the third period began, Buffalo pushed hard, aided by 46 seconds of power play time that bled over into the third period. Boston's kill survived, but midway through the third period, Jason Zucker wired a shot that tipped off Andrew Peeke and beat Swayman.

From there, it became a mad scramble to the end. Boston fought hard and gritted their way to yet another win. Sean Kuraly tucked in an empty-netter with two seconds left to put the game on ice.

The way Boston is winning continues to be the most important thing. Sturm talked about how these continual wins are how team builds things.

Today, Sturm talked about the immediate buy-in from his team, how ready they've been. Then, he tipped his hand on perhaps the biggest piece of the puzzle.

"You can see it in the game today, everyone is excited to play. Everyone works. We’re a family. That’s what family does– support each other, we help each other. That was our message."

For Kastelic, it's the energy.

"The energy in here right now is amazing," said Kastelic. "It's truly just a great room to come into every day, right from the staff down to the boys. I think everybody's just coming to the rink with a smile, hungry to work and get better each and every day."

Any way you slice it, the Bruins are 3-0-0 and tied for first in the East with Brad Marchand's Florida Panthers.

Boston has one more home game, Monday afternoon against the Tampa Bay Lightning for a holiday matinée inside TD Garden.