Duchene scored his second goal of the game with 2:24 remaining in overtime to lift the Avalanche to their fifth straight win, 6-5 over the Senators on Friday night.
"My first overtime goal. You can't beat that," Duchene said.
Duchene got hold of the puck in the Avalanche zone off a pass from teammate Tomas Fleischmann and sped down the ice before sending a wrist shot from the lower left circle past goalie Brian Elliott for the winner.
"I got a great pass and it was off to the races," said Duchene, who has 20 points in his last 14 games, including multipoint games in four of his last five. "The puck was rolling the whole time down. I just wanted to put the puck on the net. I was able to get it off the ice and it found a hole."
Duchene leaped in the air when he saw the puck go into the net and was soon mobbed on the ice by his teammates to celebrate the final twist in a dizzying game marked by constant swings in momentum.
"We played hard and we did a lot of good things," said Ottawa coach Gary Clouston. "We just didn't defend well enough, maybe, or get a save when we needed one. They're a good team and they pressure you. They make you pay for your mistakes."
Ottawa also had to make a last-minute change at goalie. Pascal Leclaire had been scheduled to start but had to be scratched in favor of Elliott after sustaining a lower-leg injury during pre-game warmups.
"It didn't really change our game plan, but it doesn't make it easy, that's for sure," Clouston said.
Brandon Yip gave Colorado its first lead at 2:08 of the third, putting a rebound past Elliott for his eighth goal of the season.
But the Avalanche couldn't hold it. With Ottawa on a 5-on-3 power play, Alexei Kovalev scored at 4:29 of the third to produce the game's fourth tie. The Senators grabbed the lead again on Daniel Alfredsson's goal at 11:15 of the third before Ryan O'Reilly, charging toward the net, converted a centering pass from Daniel Winnik into another tying goal with 3:13 remaining in regulation.
"I went glove side. The puck came to me from the other side and I saw enough net and took the shot," O'Reilly said. "There have been a few magical moments already this year."
Duchene put in his 12th goal of the season at 16:55 of the second as Colorado evened the score for the third time on the night. The Avalanche had a two-man advantage on the power play when John-Michael Liles took a shot that glanced off a defenseman's skate toward Duchene, who drove the puck past goalie Brian Elliott.
At 11:39 of the second, Ottawa slipped ahead 3-2 when defenseman Matt Carkner beat goalie Craig Anderson for his first goal of the season. Colorado had pulled into a tie a little more than a minute before when Cody McLeod poked in a loose puck from up close.
The teams ended the first period tied 1-1.
TJ Galiardi, in his first game back from a broken right wrist that had sidelined him for 17 games, tied it at 3:55, sending a shot from the right boards that beat Elliott to the glove side. A clearing pass bounced off a referee onto Kevin Shattenkirk, who set up Galiardi's shot.
Ottawa completed its sixth set of back-to-back games this season. The Senators beat Minnesota 3-1 Thursday on the front end of the set. ... Colorado RW Milan Hejduk missed a fourth consecutive game because of a groin injury and C Paul Stastny sat out with a sore back.