MONTREAL -- The Montreal Canadiens began the season with no expectations, but ended it with high ones.

Their loss in five games to the Ottawa Senators in the Eastern Conference Quarterfinals was a disappointing end to a surprising season, one that saw the Canadiens go from last in the Eastern Conference to first in the Northeast Division.

They did this with minor tweaks to the roster and one very astute trade during the season, when general manager Marc Bergevin sent Erik Cole to the Dallas Stars for Michael Ryder and a third-round pick in the 2013 NHL Draft.

Max Pacioretty

Left Wing - MTL

GOALS: 0 | ASST: 0 | PTS: 0
SOG: 13 | +/-: 0

Here are five explanations for the Canadiens' early exit from the postseason:

1. The scorers didn't score

Montreal's regular-season leader in points, Max Pacioretty, had none in four games in the series, and revealed after the team's 6-1 loss in Game 5 that he separated his shoulder in Game 1. Tomas Plekanec and David Desharnais didn't score a goal, though Plekanec had four assists, and Ryder scored once. Montreal got six of its nine goals in the series from three players: P.K. Subban, Rene Bourque and rookie Brendan Gallagher.

The Canadiens needed their offensive leaders to produce, and though they generated chances offensively, Montreal scored six even-strength goals in five games against Ottawa goaltender Craig Anderson. Though his performance was spectacular at times, it was up to the Canadiens' offensive players to solve Anderson. They didn't.

2. Mental toughness

All season, the Canadiens made a habit of starting games strong, building a lead then playing with that lead. In this series, the Canadiens did indeed start most of the games very strong, swarming the Senators goal with quality scoring chances. But when that lead didn't come -- Ottawa scored first in three of the five games -- Montreal appeared to get discouraged and desperate as the game wore on, leading to holes defensively created by players veering away from the system in an attempt to manufacture offense. The result was that Ottawa scored 12 goals in the third period over the course of the series; Montreal did not score once.

3. Injuries

It is seen universally as an excuse, and the Canadiens' motto this season, written on the wall of their dressing room, was "No Excuses." Still, very few teams would have been able to withstand the types of losses the Canadiens had in this series. They lost center Lars Eller in Game 1, a game in which Pacioretty separated his shoulder and captain Brian Gionta tore his left biceps.

The Eller injury probably was the most significant; he was Montreal's scoring leader in April with 13 points in 14 games. Goaltender Carey Price and forwards Brandon Prust and Ryan White would be the next to go down, leaving the Canadiens with a shell of a lineup in Game 5. Montreal stayed relatively free of injuries during the regular season, something that played a big factor in their success. Their inability to absorb injuries in the playoffs, however, ultimately became the Canadiens' downfall.

4. Lack of discipline

The Senators' plan to physically punish the Canadiens appeared to throw them off their game right from Game 1, when Ottawa defenseman Eric Gryba knocked Eller out of the series with a hit that cost him a two-game suspension from the NHL. Defensemen Marc Methot, Jared Cowen and Chris Phillips, along with forwards Zack Smith, Chris Neil and Matt Kassian played leading roles in causing a meltdown by Montreal in Game 3, with a combined 210 penalty minutes from the teams in the third period.

5. The power play fizzled

The Canadiens entered the series with a decided edge on the power play, but the Senators outscored them 6-3 with the man-advantage in the series, largely because they had 25 opportunities in five games. But the Canadiens clicked at a 15.8-percent success rate -- compared to 20.7 percent in the regular season -- and scored three times on 43 shots in 19 power-play opportunities, a shooting percentage of 7.0 percent. To make matters worse, the power play allowed a shorthanded goal to Kyle Turris in Game 5 that made the score 3-1, essentially putting the nail in the coffin for their season.