The Canadiens, who enter with a one-point lead over the Atlanta Thrashers for the Eastern Conference’s eighth and final playoff spot, last lost four straight from Dec. 30-Jan. 5.
The Thrashers host the Buffalo Sabres on Monday.
Despite outshooting the Pittsburgh Penguins 46-23 on Saturday, Montreal lost the game 5-4, its second one-goal loss in the three-game slide.
“This is really a tough one to swallow,” Canadiens defenseman Mathiru Dandenault said. “At this stage of the season, we needed all the points we can get.”
In addition the losing the game, the Canadiens might have also lost defenseman Francis Bouillon for a while. Bouillon left on a stretcher with a bruised left leg after falling awkwardly into the boards in the second period.
Defenseman Andrei Markov participated in Saturday morning’s skate and could return from a three-game absence due to back spasms.
Goaltender David Aebischer has allowed five goals in each of his two starts since the Canadiens acquired him in a March 8 trade with the Colorado Avalanche. Aebischer has a .844 save percentage and has yet to record a win for Montreal.
The Capitals suffered their second shootout loss in a five-game losing streak with a 4-3 defeat to Florida at home on Saturday. A sixth straight loss would match Washington’s longest losing slide of the season, from Jan. 1-12.
Chris Clark registered the first hat trick of his six-season career, and Alex Ovechkin added two assists for Washington. Darius Zubrus had an assist to extend his career-best points streak to seven games.
The Capitals are out of the playoff race again, after tying for the NHL’s second-lowest point total with 59 in 2003-04.
“We’ll just keep working on the execution,” said Washington coach Glen Hanlon, who took over after 28 games in 2003-04. “Our next step of improvement is to be close to perfect on execution of your systems.”
The Capitals have won both meetings between the clubs this season.