Roy was a third-round pick by the Canadiens franchise in the 1984 draft and spent his first 10-plus seasons with Montreal before his infamous trade to Colorado in December of 1995 after a fallout with then head coach Mario Tremblay.
During his time with the Habs, Roy won a pair of Conn Smythe Trophies and Stanley Cup titles in 1986 and 1993. He also won two Cups and another Conn Smythe award with the Avalanche.
Roy faced Montreal for the first time as a coach when the Avalanche picked up a 4-1 victory at home on Nov. 2. On Tuesday, the former Canadiens goalie coached his first NHL game in Montreal.
Brandon Prust had a goal and an assist for the Canadiens, who have won three in a row. Travis Moen and Dale Weise also lit the lamp.
Carey Price stopped 25-of-28 shots for the victors.