Hathaway made it 2-0 at 14:05. Ovechkin carried in on the right side, faked a shot and passed across to Hathaway, who knocked it in from just below the left circle for his third goal in two games.
Guentzel pulled the Penguins within 2-1 at 18:40 when he controlled the puck in front of the net, pulled it around Vanecek's right pad and tucked it in.
The Capitals made it 3-1 when Lars Eller passed across the crease to Sprong for the one-timer at 16:11 of the second.
"I think that's exactly the recipe for success for us," Eller said of the depth scoring. "We get contributions from every line we're going to be hard to play against and defend against and match up against."
Sheary's wrist shot from the right circle at 18:36 increased the lead to 4-1.
"Obviously this game got away from us there," Dumoulin said. "They scored a couple quick goals there in the second period. I thought even though they scored two early, we were coming. We just got to be better for a full 60."
Kuznetsov made it 5-1 when he scored from the slot at 4:43 of the third period, and Wilson's power-play goal on a breakaway at 9:35 increased the lead to 6-1.
NOTES: Dumoulin played 19:55 and had two hits and two takeaways. Pettersson had five hits in 17:09. Ruhwedal blocked four shots in 19:25. … Pittsburgh assigned forward Drew O'Connor, defensemen Pierre-Olivier Joseph and Juuso Riikola and goalie Louis Domingue to Wilkes-Barre/Scranton of the American Hockey League. … Capitals forward Nic Dowd, 31, signed a three-year, $3.9 million contract. Dowd, who is on the injured list (lower body), leads the Capitals in face-offs (56.4 percent) among players with at least 100 draws taken and ranks third in penalty kill time per game among forwards (1:21). … Former Penguins Sheary and Sprong have seven goals in 12 games and four goals in seven games, respectively, against Pittsburgh. ... The Penguins went 2-1-2 with assistant Todd Reirden filling in for Sullivan.