"When the pucks start going in, the confidence starts coming," said Duchene, who has 14 points (six goals, eight assists) in his past 14 games. "I felt like when I first got here there was about 10 or 15 games, and out of those games there were probably 12 of them where we just couldn't get started.
"The process was there but the results weren't. I got away from it at times and then you circle back to it and just try and come out every night and just do the right things, and it eventually goes."
WATCH: [All Devils vs. Senators highlights]
Mike Hoffman had a goal and an assist, and Craig Anderson made 30 saves for the Senators (18-25-9), who have won three of four games.
Keith Kinkaid allowed four goals on 20 shots and was pulled in the second period. Eddie Lack made 11 saves in his debut for the Devils (27-17-8), who had won three in a row.
"Four was enough," New Jersey coach John Hynes. "I thought [Lack] went in and he made some good stops. We give up a breakaway goal that he had to stop, which isn't fair to him, but I thought he came in and made some good saves and made another nice glove save in the third period. So, nice to see him get in and get his feet wet and get back to some NHL play."
Thomas Chabot passed to Colin White in the slot on a rush and he scored his first NHL goal to give the Senators a 4-1 lead at 8:43 of the second period.
"It was a great play from Chabot and Duchene there," said White, who played his 13th NHL game. "It's funny, we were shooting pucks today as a game after the pregame skate, all three of us, and then that happens, so it's pretty exciting."