Leland Irving, making only his second NHL start, won a goaltending duel with Roberto Luongo by making 29 saves.
Glencross scored his 14th goal of the campaign to give Calgary the lead and Mikael Backlund increased the Flames' advantage with 5:52 left in regulation.
Irving was called up when backup goaltender Henrik Karlsson suffered a knee injury. Irving made his NHL debut Dec. 16, and was credited with 39 saves in a 3-2 overtime loss to Florida.
Luongo stopped 28-of-30 shots for the Canucks, who had a three-game winning streak snapped. The Flames have won three in a row.