It was the first home win for the Canadiens this season, who move to a 3-1-1 record. It was also the first win for Habs goaltender Carey Price in the Bell Centre since February of this year.
Montreal outshot Ottawa 40-19, but the Senators did make it interesting, scoring twice on their first three shots in the second period.
Milan Michalek had two goals for the Senators in the losing cause.
Habs captain Brian Gionta got his team on the boards first, forcing a Senators turnover and skating in on goaltender Brian Elliott at 1:06.
The Senators replied, at 10:32, when Daniel Alfredsson's blast tipped off the glove of Price and behind his back to an awaiting Michalek.
Ottawa then scored a pair of goals just 53 seconds apart. Erik Karlsson's slapshot beat Price glove side at 10:20, and Michalek swept in past the Habs defense, beating Price to give the Senators a two-goal lead.
Montreal then got a little luck, at 13:29, when Jeff Halpern made a no-look back hand, from behind the Ottawa goal, that bounced off the skate of Senators defenceman Chris Campoli and past Elliott.
Plekanec then fed Andrei Kostitsyn, who powered his way in to tie it up at 17:29.
Price stayed unphased the rest of the game. Despite the low shot total, and many key saves when called on, notably a big glove save on Peter Regin during an Ottawa 2-on-1 rush with 1:45 left in the second.
The duo of Plekanec and Kostitsyn finished it off, when the Habs centre followed up on his winger's rebound at 16:01 of the third period.
Special teams remain a problem for the Canadiens, who went 0-for-5 on the night, and have just a single goal on 17 man-advantage opportunities this season. Rookie Lars Eller played just 4:20, and was a -2 on the night, and spent the better part of the second and third periods on th Habs bench.
Next up for the Canadiens are the New Jersey Devils on Thursday at the Bell Centre.
Three Stars: 1. Plekanec 2. Kostitsyn 3. Michalek
Montreal Canadiens Lineup
Forwards: Moen-Gomez-Gionta, Cammalleri-Plekanec-Kostitsyn, Eller-Halpern-Lapierre et Pouliot-Boyd-DarcheDefense: -Gorges, Hamrlik-Spacek, Picard-Subban
Ottawa Senators Lineup
Forwards: Alfredsson-Spezza-Michalek; Foligno-Fisher-Neil; Winchester-Kelly-Ruutu; Shannon- Regin-Kovalev
Defense: Gonchar-Phillips; Campoli-Carkner; Karlsson-Lee
Injuries: Ottawa Filip Kuba(broken leg), Pascal LeClaire (groin) Montreal: Markov (knee)
Follow the what the Sens fans are thinking at Silver Seven
On this day: Habs legend Doug Harvey played his 1st NHL game in 1947.
Cedrick Desjardins: The former Habs prospect, now property of the Tampa Bay Lightning, had a shutout in his AHL debut with Norfolk. Karri Ramo, the guy we got in the deal, is 4-3-2, 2.59 GAA, .888 SvPct with Omsk Avangard (KHL).
Bob Gainey:Has been travelling with the Bulldogs. He noted, during the second intermission, that there are 6 or 7 players on the current roster that will be in the NHL within a year or two. Didn't specifically name them, and also noted that they wouldn't necessarily be playing for the Habs.
More ammo for Leafs fans:Marlies come back from a pair of two-goal deficits to beat the Bulldogs 5-3.
MTL - Gionta (unassisted) - 1:06
OTT - Michalek (Alfredsson. Spezza) - 10:32
OTT - Karlsson (Alfredsson, Spezza) - 10:20
OTT- Michalek (Phillips) - 11:13
MON- Halpern (Subban, Moen) - 13:39
MON - Kostitsyn (Plekanec) - 17:29
MTL - Plekanec (Kostitsyn) - 16:01