"It's nice, obviously, to have the lead, but it's not always going to work out like that, so I try and, no matter what the score is, just do my job," Copley said. "And fortunately, we got the win tonight. There's plenty of different ways to win games or lose games. Sometimes you score a lot, sometimes you don't, so I just try and do my job no matter what the score is."
Brett Connolly had a goal and an assist for the Capitals (22-10-3), who are 7-1-0 in their past eight games and 14-3-0 in their past 17.
WATCH: [All Capitals vs. Senators highlights]
"It all comes back to leadership," Washington coach Todd Reirden said. "Tonight was one of our best games, in terms of that. I couldn't be prouder of our guys for rallying behind it. It was an easy game to check out and say, 'Let's just see how it goes.' Everyone was invested right through our whole lineup tonight and playing the right way for each other."
Mike McKenna made 29 saves for the Senators (15-18-4), who are 3-6-1 and have scored two or fewer goals in eight of their past 10 games.
"It wasn't a 4-0 game, that's for sure," Ottawa coach Guy Boucher said. "Our players came out strong and played really well. We got so many scoring chances. Their goalie just stoned us."
Copley extended his winning streak to four games. He is 7-2-1 backing up Braden Holtby this season.
"We talked about [Copley's shutout] in between the second and third," Connolly said. "We needed to make sure that we didn't have any defensive breakdowns and making sure that we're getting in front of shots and getting in lanes and playing hard in front of our net for him. It was good to see him get that shutout."
Connolly redirected a Jonas Siegenthaler point shot to give the Capitals a 1-0 lead 1:32 into the first period. Niskanen tipped a pass from Nicklas Backstrom at the top of the crease to make it 2-0 at 17:56.
Vrana stole the puck from Senators forward Mark Stone and finished a forehand deke into the left corner to make it 3-0 at 9:05 of the second period. Kempny gave Washington a 4-0 lead at 13:44 when his point shot deflected off Senators defenseman Cody Ceci.
