Cole Caufield then tied it 2-2 with 2:20 remaining and Montembeault pulled for an extra skater. He converted on a one-timer from below the left circle after receiving a diagonal cross-ice pass from Jonathan Drouin.
"I didn't even see the pass, and all of a sudden it's in the back of the net," DeSmith said.
Caufield said he was able to get open by reading the Penguins' defense.
"You can kind of see from my spot over there where everybody is, and you just try to get lost and time it so you come to the puck at the right time," he said. "And obviously, [Drouin] just made a [heck] of a pass. I think that one's on him. I had the whole side of the net."
Malkin put Pittsburgh ahead 1-0 at 3:52 of the second period, shooting across the grain on a one-timer from the right circle as Montembeault slid across the crease. He then made it 2-0 at 7:55 when he drove to the slot and converted on a rebound at the top of the crease.
"It's a tough loss tonight, but the team, every game we play better and better," Malkin said. "And my line, like myself, I'm trying to keep going every game. I hope (I have) no injuries again. I feel my confidence. I feel like I'm still a good player."