"Home opener, you know they're going to start pretty hard", Crosby said. "I thought we did a good job of just weathering that. When 'Geno' got that first goal, it just kind of gave us a good boost.
"And then to follow it up with some power plays and see these go in, I think we just gained momentum from that."
Spencer Carbery was making his debut behind the bench for Washington after being hired on May 30 to replace Peter Laviolette.
"It was the worst scripted start we could possibly have had in terms of just being disappointed, home ice", he said. "Trying to generate some momentum from a season standpoint, and that certainly did not happen."
"I don't want to say a better effort, I just thought we played smarter tonight", head coach Mike Sullivan said. "Just our play without the puck was a little more conscientious certainly than it was in Game 1, and I think that gives our guys an opportunity to act on the talent we have. So, we played hard tonight, but we also played smart."
Charlie Lindgren made 31 saves for the Capitals in place of starter Darcy Kuemper, who missed the game after his wife gave birth Thursday night.
Crosby, Malkin lead Penguins past Capitals
After a goalless first period, Malkin put Pittsburgh in front 4:07 into the second period after Karlsson kept a loose puck in the offensive zone, passing to Rickard Rakell, who centered it to Malkin and he beat Lindgren from the slot glove side.
Crosby doubled the lead less than two minutes later, knocking home the puck while falling down.
He scored his second from a cross-ice pass by Malkin that was one-timed from the bottom of the right faceoff circle with Pittsburgh on the power play.
Jarry preserved the 3-0 lead after saving an Alexander Ovechkin breakaway attempt with his pad with 4:07 left in the second.
Ovechkin finished with four shots in 18:42 of ice time.
"I think we played well in the first period", he said. "Second one, we didn't score. They scored, and that's kind of the game."
Smith, acquired by the Penguins in a trade with Vegas on June 28, scored his first goal with the club as his shot from the left faceoff circle beat Lindgren off a pass from Malkin with 3:03 left to play.
"I thought Geno was on his game tonight", Sullivan said. "When he's on his game, it seems like the puck follows him around. ... That play he made on Reilly's goal at the end, just an unbelievable pass. It started with a track, just tracking the puck from behind.
"He was playing at both ends of the rink. He's competing hard. I just think when he's on his game, he's as dominant player as there is in the league."