Eller made it 3-0 on a wrist shot from just outside the crease after Panik passed between Kris Letang's legs at 1:09 of the third period.
"[The Penguins] are a good hockey club over there," Capitals forward T.J. Oshie said. "We've had some trouble with them this year. Defensively, offensively, special teams-wise, I think that's our most complete game of the year. Something to be happy about and build on going forward here."
Aston-Reese cut it to 3-1 with a wrist shot at 15:05 of the third. He has one goal in each of his three games since returning from offseason shoulder surgery.
"I had mentioned last week, a lot of hesitation giving and receiving hits," Aston-Reese said. "Having to get surgery kind of made me take a step back and think about why I have been getting injured and what I can change. I did change a few off-ice habits. Clean up up my diet. … Bunch of little things, but they all add up, and I think it's starting to show."
NOTES: Capitals forward Nicklas Backstrom (19 points; seven goals, 12 assists) had an assist on Vrana's goal. He has at least one point in 12 of 14 games this season, tied with Bruins forward Brad Marchand for the most games with a point in the MassMutual East Division. ... Penguins defenseman Marcus Pettersson returned after missing nine games with an upper-body injury. He had two shots on goal and one hit playing 14:19. … Pittsburgh's line of center Sidney Crosby, left wing Jake Guentzel and right wing Bryan Rust combined for three 5-on-5 shots. It combined for eight points (four goals, four assists) on Sunday.