The Canadiens were eliminated by Ottawa in five games in the first round of the 2013 playoffs, and a few of the returning players remember that series well.
''It's not something I've ever forgotten,'' said Brendan Gallagher, one of 10 Canadiens who was on Montreal's playoff roster two years ago.
''You don't think about it too much, but if you're not learning from your past experiences, you're not going to get better.
''For us to learn from that series and make sure it doesn't happen again is something on our mind.''
After the lockout-shortened 2013 season, the second-place Canadiens were considered favorites to beat the seventh-place Sens.
But Michel Therrien's team was hit with several injuries, couldn't solve goalie Craig Anderson and were ultimately outscored 20-9. In the finale, the Habs lost 6-1 in front of their home fans.
''I remember it,'' said Alex Galchenyuk, who had three points in that five-game playoff series. ''I want to beat these guys because they stopped us two years ago. You want to get back at them.
''We don't think about it too much. Whatever happened stays in the past. But we remember that they beat us, and we have to come in with more energy and more fuel.''
The scenario this postseason is similar to the one two years ago.
The Canadiens finished second in the Eastern Conference this season while the Senators were seventh. Ottawa also has a hot goalie in Andrew Hammond, whose 20-1-2 record backed the Sens' improbable end-of-season run to the playoffs.
''My approach is just going to stay the same,'' Hammond said. ''At the end of the day we feel like we've been playing playoff hockey for a while now. We've been playing a lot of close games and our approach has gotten us this far and I'm no different, so I don't see the point in really changing things.''
''I expect to win (the series),'' Senators coach Dave Cameron said. ''I'm sure the guys in the room expect to win it. I'm sure Montreal expects to win it. I would be really disappointed going into a playoff series if we didn't expect to win it. I would be shocked.''
''We haven't really looked much at statistics,'' he said. ''There's no point of over-analyzing numbers, it's not going to help us. The playoffs are a new situation where the past doesn't matter.
''It's just motivation for us. There's no dwelling on the past from our side.''
That series loss in 2013 was a rude awakening for Gallagher, though, who had never experienced playoff hockey prior to that matchup.
Gallagher says Montreal's deep playoff run last year - the Canadiens made it all the way to the Eastern Conference finals - will make a difference against the Senators this time.
''It's about understanding what it takes to get to the next level,'' he said. ''As you're going through, you learn what it takes as a team and individually - how you handle different situations and your emotions.''
Though he practiced with the team on Tuesday, Pacioretty was not a member of an attacking trio nor did he take part in team exercises involving contact.
''The medical staff has not told us yet that Max is going to be there for tomorrow,'' said Therrien, who added Pacioretty was in fact cleared for contact. ''Maybe he will, but we're not quite sure. I will be surprised (if he plays).''
Notes: The Canadiens went 1-3-0 against the Senators this season. They were outscored 14-9. Mark Stone scored two game-winning goals for Ottawa against Montreal this year. Pacioretty scored four goals against the Sens this season.