BOSTON –– Marco Sturm could not exactly put it into words.​

The head coach attempted to describe the togetherness the Boston Bruins displayed in their 3-1 win over the Buffalo Sabres on Saturday at TD Garden. It is more of a feeling that has surrounded the team since Sturm’s first day, though.​

“The guys, they buy in. I don’t know what else to say,” Sturm said. “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.”

Unity has been a consistent message amongst both the veterans and young faces in the Bruins locker room, earning the group a 3-0-0 record to start the year. Despite the close score of Saturday’s game against the Sabres, Boston felt in control until the final buzzer.​

“I think that’s something that is kind of a strength of our team,” Pavel Zacha said. “I think the last three games, we’ve been able to finish the games and win them.”

​Zacha capitalized on a shot-dominant opening frame from the Bruins. The forward ripped a one-timer from the left circle for his first goal of the season and a 1-0 lead at 15:48. It extended Zacha’s point streak to three games, too.​

Jordan Harris, who made his Bruins debut, got the primary assist on the play, marking his first point with the organization. The Haverhill, Mass, native skated on the second pair with Andrew Peeke and finished with an assist, block and two hits through 16:25 of ice time.

“Really good. He came in and felt like he was playing every game so far this season.” “Smart with the puck, simple,” Sturm said of Harris. “He can skate. Had some really good sticks, even for his size. He was always in a good spot. I was really happy about his game.”

BOSTON –– Jordan Harris was once a 10-year-old sitting in the crowd at TD Garden, cheering on his hometown team. Now, the Haverhill, Mass, native will be on the other side of things, sporting the Spoked B on the ice.

The defenseman, who signed a one-year deal with Boston in July, is making his Bruins debut on Saturday at 7 p.m. as they face the Buffalo Sabres.

​“Just really excited, looking forward to it. Probably be some nerves closer to game time,” Harris said. “I have some family coming and some buddies coming. We’ll see who ends up showing up.”

​The 25-year-old spent last season with the Columbus Blue Jackets and is looking to further prove himself at the NHL level in Boston. Harris had a strong training camp, rotating through different D-partners. He is expected to skate on the second pair with Andrew Peeke against Buffalo.

​“It’s a blessing every day you play in this league, and you play hockey for a living. Every single day is an opportunity, every time you step on the ice,” Harris said. “Since the day I signed, it’s just been what can I do today to get better, improve my game and show what I can do.”​

While Saturday will be his first game at TD Garden as a member of the Bruins, Harris has had some monumental moments on Causeway Street during his early hockey career. He played four seasons of NCAA hockey with Northeastern University from 2018 to 2022, and won both the Hockey East Championship and Beanpot at TD Garden in the 2018-19 season.

“​I’ve said this to everyone – it’s got to be the best barn in the league, if not up there,” Harris said.

Simons made 6 of his 13 shots and lived up to his reputation as an offensive force. Defensively, he showed effort but struggled on ball, especially against Raptors rotation player Gradey Dick.

“I was a little nervous at first, but I think in the second half I calmed down and started to play my game a little bit more,” Simons said. “I was nervous about being back out there and a new team. [Mazzulla] didn’t say nothing about the fouls, but I knew I needed to chill out with the fouls.”

Simons rested in the preseason opener as Mazzulla went with four projected starters in the 121-103 win over the Grizzlies. This time he opted for Simons and Payton Pritchard, who scored 19 points. Chris Boucher, in his return to Toronto after seven seasons with the Raptors, scored 19 on 7-for-10 shooting.

Looking for more consistency, especially with rebounding, Mazzulla deployed his players in hockey-type shifts, pulling all five players from the floor when they couldn’t collect a defensive rebound. In one sequence, he pulled rookie Hugo González after less than a minute, then threw him back into action with the next shift.

There were several occasions in the first half where players logged less than a minute but eventually returned to the game. Boston ended the half on a 20-3 run sparked by a Pritchard heater for a 63-42 lead.

The Celtics led, 103-89, with 3:45 left before a disastrous final stretch where they committed eight turnovers and were outscored, 18-2. Mazzulla used Baylor Scheierman and the two-way contract players, and they struggled to even get the ball up the floor.

“That’s good,” Mazzulla said of the experience for the rookies. “Those guys have to get those reps. They have to be able to execute. They have to understand every possession matters. I thought Toronto did a good job turning up the pressure and we have to continue to work through executing. Whoever it is out there.”

The Celtics, who rested Jaylen Brown, Derrick White and Sam Hauser, finished with 29 turnovers, 21 in the second half.

. . .

Mazzulla was not pleased with Scheierman early in the fourth quarter Wednesday against Memphis and the second-year swingman struggled against the Raptors, with six fouls and five turnovers. In the first two minutes of the final period against the Grizzlies, Scheierman committed two live-ball turnovers (Mazzulla’s absolute most-despised error) and missed three contested 3-pointers.

After the third miss, Mazzulla looked back at his bench and told his assistants he couldn’t watch anymore, replacing Scheierman with training camp invite Jalen Bridges. Ninety-eight seconds later, he reinserted Scheierman, who then responded with a rebound and step back 3-pointer. Mazzulla screamed at his second-year player, “Welcome to the game!”

More is expected from Scheierman in his second season as he vies to fill an energy and defensive role on the second unit. Mazzulla said that growth will be a process.

“He’s a smart guy and he plays really hard,” Mazzulla said. “But that segment was an important segment for a young player to understand, especially at the start of the fourth quarter. Those momentum swings regardless of the game, you have to play really hard, but you also have to have situational awareness. Those are the things you really have to grow at as a player and as a team because a 20-point lead at the start of the fourth quarter, as we know, means absolutely nothing.

“But he’s great, wants to be coached, plays really hard. Last year he did a great job of delivering in that Brooklyn game at home. That was the breakout and now the expectation is to do it every night and do it physically and also mentally.”

. . .

Mazzulla was annoyed by a report that indicated González, who is multilingual and speaks Spanish as hisprimary language,was having trouble comprehending English during training camp. González told reporters last week after practice he was learning the language of the offense, which was misinterpreted as English.

“Who reported that he was having language barriers?” Mazzulla asked. “Someone put that out there. He’s not. He speaks multiple languages and I think people should speak to him in his native language. For anybody in the media that can speak Spanish, you should talk to him in Spanish. I didn’t like that headline because he doesn’t have an issue understanding that. I was pretty [upset] about that.”

Gary Washburn is a Globe columnist. He can be reached at gary.washburn@globe.com. Follow him @GwashburnGlobe.