With the score tied 3-all, Gionta was credited with his second goal of the game when his shot, which was initially saved by Gustavsson, bounced off defenseman Brian Lashoff's skate and into the net. Galchenyuk added a fifth for the Canadiens two minutes later.
Montreal remained in second place in the Atlantic, four points clear of division-rival Tampa Bay, which lost on Saturday.
With Montreal up 3-0 going into the third, Detroit made a game of it with two goals in 36 seconds. Datsyuk scored his 16th of the year at 5:11 on the power play, and Glendening reduced the deficit again at 5:47 on a soft backhand shot that Price got a piece of.
Kronwall tied it up for Detroit midway through the period, beating Price with a slap shot from the point on the man advantage.
Despite the loss, the Red Wings are holding on to the first of two wild-card spots in the East.
Montreal opened the scoring when Bournival got his seventh of the year - and first in 37 games - with 5:44 left in the first period.
The rookie got the play going, intercepting the puck in the neutral zone before feeding Ryan White at the blue line. White held off defenseman Kyle Quincey and took a weak backhand shot on Gustavsson, who kicked the puck straight to a wide-open Bournival.
Pacioretty made it 2-0 on a great individual effort at 8:52 of the second, going around Kronwall with speed at the Canadiens' blue line to generate a breakaway. Pacioretty fended off a diving Lashoff before beating Gustavsson blocker-side for his ninth goal in his last eight games.
With his 39th goal, Pacioretty moved into a tie with San Jose's Joe Pavelski for third in NHL scoring.
Gionta got in on the action 5 minutes later, scoring his 16th of the season after a set play off the end boards landed perfectly on his stick, unmarked in front of the net. The goal was Montreal's second in the period on only their third shot.
NOTTES: The Canadiens play three more times before the start of their first-round playoff series. ... The game was Gionta's 300th with Montreal. ... D Douglas Murray served his second of a three-game suspension for his elbow to the head of Tampa Bay's Mike Kostka. ... The Red Wings are seeking a 23rd consecutive playoff appearance.