Erik Karlsson tallied a goal and added an assist, Peter Regin added a goal and Daniel Alfredsson notched two assists as the Senators snapped a five-game losing streak and moved two points ahead of Montreal and Philadelphia into sole possession of the fifth place in the Eastern Conference.
Ottawa will play in Philadelphia Tuesday in a key conference match-up.
The Canadiens dropped their second straight as Jaroslav Halak registered 25 saves in the defeat.
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