BOSTON — Two games. Two wins. The Boston Bruins are already rolling downhill.

Coaching matters.

Marco Sturm’s priorities were not to fix the power play, straighten out the goaltending or find offensive depth. The rookie coach believed those things would take care of themselves if he first wrapped both hands around the No. 1 problem: identity.

Sturm is off to a roaring start when it comes to that. After leading a blue-collar training camp and issuing regular reminders to play hard, Sturm’s message has rapidly gone viral within the room.

“Those are the kinds of wins you need to build something — what we want to build here,” Sturm said, sharing hockey operations adviser and mentor Zdeno Chara’s postgame declaration, after Thursday’s 4-3 overtime victory over the Chicago Blackhawks. “It’s not always pretty. But the guys got the job done. It’s not easy to play a game like that.”

Joonas Korpisalo made three saves in overtime, including two on prime scoring chances. (Rich Gagnon / Getty Images)

The Bruins grabbed four points with back-to-back wins over the Blackhawks and Washington Capitals.

Sturm had his hands all over the results. Here are five ways:

No defensive crumbling

At 12:23 of the first period, after sharing a word with head physical therapist Joe Robinson on the bench, Hampus Lindholm retreated to the dressing room. He did not return. Sturm said Lindholm had suffered a lower-body injury unrelated to his broken patella. Lindholm is scheduled for tests today.

“We’re going to be smart,” Sturm said. “We need him for the long run. Sounds like it’s not too bad. But we’ll see (today).”

Lindholm’s early departure could have caused the blue line to wobble. But Sturm and assistant coach Jay Leach kept a firm hand on the defensemen. The Bruins allowed two five-on-five goals after Lindholm’s exit. One of them skimmed past Joonas Korpisalo after deflecting off Tanner Jeannot.

Charlie McAvoy (27:26 of ice time) and Nikita Zadorov (25:11) emerged. Zadorov (3:47) and Andrew Peeke (3:30) did most of the penalty-killing heavy lifting.

“Physicality is huge for us,” Casey Mittelstadt said. “Especially against a young team tonight. We tired them out a little bit. We could have ended it before OT.”

Trusting the kid

Sturm has taken to Fraser Minten quickly. It’s easy to understand. Minten plays a hard, responsible, straightforward style as No. 3 center between Jeannot and Mikey Eyssimont.

“Very simple,” Sturm said of his third line. “They like to grind. They like to work. Defensively responsible. They’re killers for me. They do exactly what I want from a third line.”

Third-line centers don’t always get the coach’s nod for three-on-three overtime, though. It’s usually where the skilled pivots get the shifts.

But Sturm had Minten on the ice for OT. It was a good thing. After pulling the puck out of a pile in the defensive end, Minten took off for a two-on-one rush with Morgan Geekie. Minten thought about feeding his teammate but saw Sam Rinzel’s stick occupying the passing lane. So Minten loaded the puck on his stick and snapped the winner past Arvid Soderblom.

“I was thinking pass,” Minten said. “Geeks has got a great one-T. I was looking there. Then saw it was taken. So I tried to throw a little deception in.”

Sticking with the rotation

Jeremy Swayman was one of the Bruins’ best players against the Capitals. Swayman stopped 35 of 36 shots. According to Natural Stat Trick, he saved 3.33 goals above expectation.

Sturm would not have been faulted had he gone back to Swayman a night later. But it was a 7:30 puck drop Wednesday. The team returned to Boston at approximately 2 a.m. Thursday morning. Korpisalo was Sturm’s goalie.

Korpisalo responded with two OT showstoppers. He got his stick on Frank Nazar’s point-blank slot shot with a desperation lunge, recovering because he had overplayed the situation. He followed that up by gloving Connor Bedard’s riser on a two-on-zero rush.

“That was probably the best save I’ve ever seen in person,” Mittelstadt said of the stick save on Nazar.

Sturm has repeatedly noted the difficulty of the compressed schedule. The Bruins play the Buffalo Sabres on Saturday to complete a three-in-four set. He’ll need both goalies.

Adjusting the No. 2 line

Mittelstadt scored the game’s opening goal. He nearly set up Viktor Arvidsson for another later. He has a soft touch on the puck — in more ways than one.

Mittelstadt has a tendency to be careless when he controls the puck. It doesn’t make him dependable. Sturm gave him the least amount of ice time among his four centers against the Capitals. On Thursday, Sturm even shifted Mittelstadt to left wing, replacing him with Pavel Zacha.

“They had a decent start,” Sturm said of the second line. “Then they had a long stretch where there was nothing really going on. I just tried to spark the line a little bit. That’s pretty much it. Zachs played in the middle. Casey played on the left. Just give it a little different flavor just to get more out of them.”

Zacha led all forwards with 21:31 of ice time. Mittelstadt played 16:28. Sturm might have to keep a close eye on Mittelstadt’s usage.

“I think (Thursday) was better than (Wednesday),” Mittelstadt said. “Just a matter of keep building and keep moving forward.”

All for one, one for all

Sturm has made team togetherness non-negotiable. So he liked it in the third period when Zadorov and Sean Kuraly became violent after the Blackhawks came in hot on Korpisalo. Zadorov and Kuraly were called for roughing.

“Our goal was to create an identity here and be hard to play against,” Sturm said. “We got the right guys for it in the summer. Those are the guys who are leading the way. The rest follow. That’s nice to see. It’s only two games. But so far, I’m not really surprised about my team. Because since Day 1, they’ve been all dialed in.”