Max Pacioretty scored the tying goal in the third period and Desharnais put Montreal ahead to stay, leading the Canadiens to a 4-3 comeback win over the Boston Bruins on Sunday in a matchup of the Eastern Conference's top teams.
Both goals came with Chara sitting in the penalty box.
"It's big," said Desharnais, who also scored in the first period. "He's a key player for them. For him to not be on the ice is good for us, and we took advantage of it."
Tomas Plekanec had the other goal for the Canadiens, who jumped two points ahead of Boston for first overall in the conference.
Last season, Montreal finished out of the playoffs -- 28th in the 30-team league. This year, the Canadiens are off to a 14-4-4 start.
"We're coming from a long way," Montreal coach Michel Therrien said. "Everyone knows if we stick to our plan we've got a chance to win every game."
The longtime rivals played an up-and-down clean first period before some bad feelings surfaced late in the second. Alexei Emelin appeared to cross-check young Bruins star Tyler Seguin on the right hip, sending him to the ice in pain.
Chara then raced in, nailed Emelin, and the pair squared off to the left of Montreal's net, with the Boston captain throwing most of the punches. Seguin headed down the ramp toward the dressing room, but came back to the bench a few minutes later. Chara collected an instigating penalty, fighting major and 10-minute misconduct, leaving Boston short-handed on defense for a good portion of the third.
"The guy just broke his stick cross-checking Tyler and went down," Chara said. "I was just reacting to it. He's one of our best players and I'm not going to just watch him getting crushed like that."
That's when the Canadiens made their push, grabbing the lead.
"We were able to capitalize off the loss of Chara," Therrien said. "Everyone knows he's one of the best defensemen in the league."
Pacioretty's slap shot from the point beat Tuukka Rask, who appeared to be screened, and tied it at 3-all 5:31 into the third period. Desharnais scored out of a scramble in front with 10:43 to play.
Chara's teammates felt his actions were justified.
"Z knows the right time to step up and fight for his teammates -- and tonight was the right time," Bruins winger Brad Marchand said. "One of our guys that plays a lot of minutes takes a good shot."
Bruins coach Claude Julien was even more upset.
"The frustrating part is you end up with 17 minutes in the penalty box when you should have been on the power play," he said before challenging the Canadiens, stating they faked some hits for penalties.
"There was a lot of embellishment. That was embarrassing tonight. They have over 100 power plays and we all know why watching tonight. The embellishing is embarrassing for our game."
Peter Budaj made 31 saves for Montreal, which played the first of five straight road games.
Boston pulled Rask with 70 seconds left for an extra skater, but Budaj stopped Seguin's bid from close in the final seconds.
"Fortunately I was able to read it," Budaj said. "It was a big save."
Trailing 2-1 early in the second period, Boston tied it on Bergeron's goal. Seguin, who scored the Bruins' first goal, made a cross-ice pass during a 2-on-1 break. Bergeron knocked in his own rebound after Budaj stopped the initial shot from the edge of the crease.
The Canadiens nearly regained the lead when Pacioretty clearly beat Rask with a blast from the right circle, but it caromed off the left post. Less than a minute later, Travis Moen broke in alone, but Rask dropped to his knees to cut down the angle and make the save.
Boston then grabbed its only lead of the night on Hamilton's goal while the teams were skating four aside. Marchand fired a shot from the right circle that rebounded over to Hamilton, who slipped a tough-angle shot by Budaj from the bottom of the left circle for his second career goal.
Shortly after Boston had moved ahead 3-2, Montreal peppered Rask with a number of good chances during a 5-on-3 power play.
The Bruins did a number of different things during the game to support Newtown, Conn. One was having Sandy Hook Elementary School's lead teacher, Natalie Hammond, drop the ceremonial first puck. ... The Bruins next play at Washington on Tuesday. ... Boston F Chris Bourque was a healthy scratch. ... The Canadiens continue their road trip at the New York Islanders on Tuesday before playing at Carolina, Tampa Bay and Florida, respectively. Their next home game is March 13 against Ottawa. ... It was the 719th meeting between the teams, second only to Detroit-Chicago's 724. ... Boston entered the day leading the league with a 91.9 percent penalty killing success rate, but gave up a power-play goal after allowing two Saturday against Tampa Bay.