Craig Anderson made 34 saves for the Senators (21-30-11), who have scored one goal in their past two games; they lost 5-1 to the Winnipeg Jets on Thursday.
"Take nothing away from [the Canadiens]," Ottawa coach D.J. Smith said. "They forecheck and they work really hard. It's one of the most competitive teams that we've played in a while. They really come at you and then, obviously, they have good goaltending to back it up."
The Canadiens took a 1-0 lead at 1:13 of the first period on their first shot. Domi deked Anderson, who dived to try to poke-check the puck, and scored into an open net.
"I think we're a team that really relies on a good start and using our speed," Domi said. "That's a good hockey team over there. They work hard every shift, and I think we brought it for a full 60 minutes."
Anderson later misplayed the puck to Domi, who scored on the power play to make it 2-0 at 10:20.
"It was just the way the game flow went," Anderson said. "They came out flying. Their forecheck was pretty strong, and we weren't as good with the puck as we normally are back there. They took advantage of it and jumped out to the lead."
Byron scored from the slot to make it 3-0 at 17:58 of the second period when he intercepted the puck after Senators forward Nicholas Paul turned it over in the corner.
"Byron is probably the most underrated player in the entire NHL," Domi said. "He's unbelievable. I absolutely love playing with a guy like that. He's got so much speed, he works so hard, he's an absolute warrior. He's the kind of guy you win with."
Senators defenseman Thomas Chabot left the game midway through the first period with a lower-body injury after taking a hit into the end boards from Canadiens forward Brendan Gallagher.
"We think [Chabot] is all right," Smith said. "It's nothing major, anyways. He certainly couldn't have played, but we're hoping he's back fairly quickly."
Ottawa forwards Vladislav Namestnikov and Tyler Ennis were scratched for precautionary reasons. The NHL Trade Deadline is Monday.
