When Elias Lindholm joined NESN’s Judd Sirott during the first intermission in Calgary on Tuesday night, he called the Bruins’ first half “brutal” and said it “couldn’t get much worse.”

He was wrong about the second part. Despite Boston’s poor start, the score was still 0-0 after 20 minutes. Less than 90 seconds into the second period, the Flames had taken a 2-0 lead on goals from Matt Coronato and Nazem Kadri, just 27 seconds apart. Things had gotten worse and any hope that Saturday’s win in Vancouver would have turned this road trip west seemed to be fading.

But unlike the first two games of this trip in Winnipeg and Seattle, when the Bruins failed in the third period, they managed to overcome a two-goal deficit in the last 20 on Tuesday night and win 4-3 in overtime Pastrnak’s walk-off.

It actually looked like the comeback had begun in the second period. Interim coach Joe Sacco called a timeout right after Calgary’s second goal, and that seemed to calm the Bruins. He also adjusted his lines, moving Charlie Coyle to the right wing of the second line with Brad Marchand and Elias Lindholm, while moving Justin Brazeau to a revamped third line with Mark Kastelic and Trent Frederic.

After that, the Bruins started playing better and cut the lead to 2-1 thanks to a good shot from Lindholm, who deflected a shot on one side and finished on the other side, scoring his first goal in 12 games.

However, the Bruins fell back into a two-goal hole late in the second period as the defense was lax and Ryan Lomberg made a lucky jumper to extend Calgary’s lead to 3-1.

That could have been disappointing, but the Bruins made sure it wasn’t. In the third round they came out flying and started to create some bounces of their own. They cut the lead to 14-14 at halftime when Mason Lohrei broke his stick on a one-timer, only to have the puck slide perfectly to a pinching Andrew Peeke. His shot then produced a rebound which Morgan Geekie was able to convert.

Two and a half minutes later, Lindholm set up another goal by scoring and sending Marchand into the offensive zone. Marchand then fed Marc McLaughlin, and McLaughlin followed up his first try and buried the second to end the game with his second goal in as many games.

“Marc just rushes into the net there and stays there,” Sacco said. “This is a second division league and it was a good second attempt from Marc.”

The Bruins have to make a decision with McLaughlin in the next few days. For now, they could still send him back to Providence without exposing him to waivers. But if he were to play two more games, he would have to clear waivers to get back out, and there’s a chance another team could claim him given his recent performance. So the Bruins either send him down now, even though his play doesn’t warrant it, or they probably keep him in Boston for a lot longer.

The Bruins eventually outscored the Flames 15-5 in the third period and had a 9-1 advantage in dangerous chances. They carried that momentum into overtime and scored two big points.

“I just will,” Sacco said of the comeback during his postgame interview on NESN. “I really enjoyed our performance in the third period. There was no giving up. The snakes that were hopping over the bench were desperate to get out. They wanted to make a difference. … I was really proud of the way we responded in that third period. I loved our energy.”

As unlikely as it would have seemed this time last week, the Bruins are now 2-2-0 on this trip and have a chance to make a winning trip to Edmonton on Thursday. However, this could be the toughest test yet as the star-studded Oilers have won eight of their last 10 games.