Canadiens Christopher Higgins celebrates his goal. (CP PHOTO/ Ian Barrett)
It was a second straight win for Montreal (31-25-6) following a six-game losing streak and a second win in a row for rookie Jaroslav Halak, called up Friday to replace injured No. 1 goalie Cristobal Huet.
Garth Murray added an empty-net goal, his first of the season, and Duncan Milroy picked up his first NHL point with 58 seconds left for Montreal. The win, combined with losses by Carolina and Toronto, put the Canadiens into seventh in the Eastern Conference.
Higgins left the game after putting a hit on Washington defenceman John Erskine in the third period and did not return. There was no immediate word on his condition.
Jamie Heward and Brian Sutherby scored in a 30-second span early in the second frame for Washington (23-28-9), while Alexander Semin added his 32nd of the season on a power play.
The Capitals have not won in four games and are 4-11-2 in their last 17.
It was another quiet night for Caps' star winger Alexander Ovechkin, who was held without a point and has just one goal and one assist in his last eight games.
The Capitals, with Brent Johnson replacing injured No. 1 goaltender Olaf Kolzig, took six minor penalties and surrendered three power-play goals in the first. Two were by Higgins, who ended a 16-game goal-scoring drought.
Higgins was at the side of the net to bank a shot in off Johnson at 7:33. Ryder drilled a shot into the far corner from the left circle at 14:48 and Higgins redirected a pass from Saku Koivu at 15:37. Koivu assisted on all three goals.
Heward's point shot went in off Brian Sutherby at 2:06 of the second, then the veteran defenceman scored himself when his long shot was tipped past Halak by Montreal centre Maxim Lapierre.
Ryder got one back shorthanded as he turned Semin inside out and scored at 16:01. It was Montreal's league-leading 16th short-handed goal of the season and beat the team record of 15 set in 1995-'96.
Then it was Semin's turn to fly past Sheldon Souray and go in alone to score on a power play with 34 seconds left in the period. Heward got his third point of the game with an assist.
Notes - Kolzig (knee) missed a third game, while Kris Beech, Ben Clymer and Steve Eminger were healthy scratches for Washington . . . Montreal was without RW Alex Kovalev (elbow), Huet (hamstring), D Craig Rivet (pneumonia) and centre Steve Begin (broken foot).