Valeri Nichushkin and Parker Kelly scored for the Avalanche (35-7-9), who have lost five of their past seven games (2-3-2). Mackenzie Blackwood made 18 saves.
“You’re going to face adversity, there’s no question, right?” Colorado coach Jared Bednar said. “… We have to find a way to bounce back again and then string a couple of games together. But it never hurts to go through a little bit of a stretch where you have to push and play your best, and you got to respond.”
After a scoreless first period in which Ottawa outshot Colorado 9-4, the Senators struck first in the second.
Nick Cousins gave Ottawa a 1-0 lead at 3:21 after he collected a long stretch pass from Zub at the blue line, skated in and beat Blackwood with a backhand.
“I think everybody was on board tonight,” Cousins said. “Every line contributed, and obviously got some big saves from [Reimer], and we’re going to need those down the stretch here.”
Kelly tied it 1-1 at 14:05 when a dump-in by Keaton Middleton was tipped by Brock Nelson and landed on the stick of Kelly, who snapped a shot past the blocker of Reimer. It was his third goal in five games.
“Couldn’t really keep sustained O-zone time to even get shots,” Kelly said. “So not good enough for us tonight, and we’re going to have to grind one out tomorrow in Montreal.”
Just 17 seconds later, Ridly Greig restored Ottawa’s lead, 2-1, at 14:22. He won a race to the puck against Middleton after it caromed off the end boards behind Blackwood and lifted a shot over the goalie’s right shoulder.