MONTREAL – Despite their best efforts, the Penguins’ success in the second leg of a back-to-back continued.

After a horrid opening period, the veteran Penguins turned it on in the second en route to scoring a 4-3 win, courtesy of a shootout, Wednesday night against the Montreal Canadiens at Bell Centre. Jansen Harkins provided the golden goal in what was the longest shootout in Penguins history.

With the victory, the Penguins’ record remained perfect, 4-0 this season, when playing in a game a day after another contest.

Despite trailing 3-1 after the first 20 minutes, the Penguins roared back thanks to a suddenly red-hot power play. A night removed from putting an end to an ugly 0 for 37 stretch that spanned 13 games, the Penguins struck twice with a man advantage.

Jake Guentzel, who scored the Penguins’ first power play goal in a month during Tuesday night’s win against the Arizona Coyotes, got another that cut the visitors’ deficit in half. Sidney Crosby, who had punched in his 16th goal of the year earlier in the contest, brought the tally even soon after another Montreal penalty.

Of course, the Penguins had nowhere to look but internally with respect to their brutal start. Erik Karlsson twice coughed up the puck in the opening period, the blueliner’s second turnover paving the way for David Savard to pocket his first goal of the year. The Canadiens doubled up their lead not long after when Jayden Struble punched in a loose puck off the rush.

While Crosby temporarily stopped the bleeding with his 16th goal of the year, Montreal pushed its lead back to two before the end of the opening period. Jay Monahan tucked in a power-play tally shortly after Marcus Pettersson took an interference penalty.

Alex Nedeljkovic, making his first start in net since Dec. 4, couldn’t prevent former Penguin Mike Matheson’s shot from sneaking through his pads, allowing Monahan to tap in the last goal of the first frame.

The Penguins’ strong second period, though, ultimately forced play to extend past regulation.