BUFFALO —  The Boston Bruins couldn’t have responded any better.

A mere 24 hours after their ugly season-opening performance against the defending Stanley Cup champion Washington Capitals, the Black and Gold came out flying against 2018 top overall pick Rasmus Dahlin and the upstart Buffalo Sabres.

“We all knew to a man — from the coaching staff on down — that we weren’t good enough last night. So we needed to be better tonight, and we were,” head coach Bruce Cassidy said. “Guys who led, led and the followers, followed. So that’s kind of the way we scripted, and it worked for us tonight.”

Here is what we learned as Cassidy and company began Atlantic Division play with a 4-0 victory at KeyBank Center Thursday night.

Veterans lead by example

Wednesday’s 7-0 blowout loss in the nation’s capital didn’t sit well with the Bruins. They showed very little competitive spirit, aside from Brad Marchand’s response to Lars Eller’s celebration and Sean Kuraly’s bout with Madison Bowley. Both fights took place with the game well out of reach.

Games like this are ideal for veterans to step up and contribute. The Bruins’ vets did just that.

Whether it was Marchand dishing out a career-high four assists, Patrice Bergeron’s stellar two-way play, David Pastrnak saving a goal and dangling through defenders, or captain Zdeno Chara sneaking through the back door for the Bruins’ first goal of the year, Boston’s core set the tone in their bounce-back performance.

“It was big,” Chara said. “We talked about it, and that’s our job — to lead this team and put yesterday behind us. It’s going to happen. It’s unfortunate because that’s not the outcome we wanted, but we moved on and turned the page and got ready for tonight’s game.”

Halak sharp against his “former” team

Jaroslav Halak appeared poised for a solid career following his stellar 2010 playoff performance with the Montreal Canadiens.

The goaltender’s journey since then has taken some interesting turns.

Now at his sixth NHL stop following stints with the Blues, Capitals, Islanders and a very brief five-day tenure with the Sabres, Halak is settling into a backup role behind Tuukka Rask. The Slovak spelled Rask in the blowout in DC, and fared slightly better in relief. So, it came to few as a surprise when Cassidy announced Halak as his starter several hours prior to puck drop.

Advantage, Cassidy.

The Bruins D gave Halak plenty of time and space to track the puck. In the rare instances where the Sabres found prime scoring chances in the slot, Halak stood tall under the pressure.

All this led to Halak earning a 32-save shutout against his “former” team.

“Yeah, right? Five days,” Halak joked about his stay in Buffalo before being traded to the Caps at the 2014 trade deadline.

“Most of the time, I was able to see the puck really well, and the guys [in front of me] did a good job,” Halak added about his first start in a Bruins uniform. “If there was ever anything laying in front, they did a good job clearing the puck. So, like I said, from top to bottom I thought it was a great team effort.”

Don’t call it a goaltending controversy quite yet, with just two games gone. Regardless, the Bruins — including Rask — will only benefit from a strong year out of Halak.

Bjork’s return highlights lineup changes

Anders Bjork entered his rookie season as one of several highly touted prospects in the Bruins’ system; however, injuries and frequent trips back and forth to Providence threw a curveball to his initial development.

Thursday marked Bjork’s first appearance since his season-ending shoulder injury on Jan. 30. After the lengthy wait, the 21-year-old had a quiet but solid return, skating with fellow linemates Danton Heinen and Sean Kuraly.

The trio got pucks in deep and kept the Sabres D on their heels when they touched that ice — a simple yet productive strategy that paid dividends.

“Something we wanted to do was play in their end and control the puck, and not give it up easily,” Bjork said after tallying 11:34 of ice time in his 2018-19 debut. “I think we did that well for the most part.”