Victor Rask had a goal and an assist for the Hitmen (17-5-3), who have won four straight games and nine of their past 10, and Pavlo Padakin scored the other.
Elgin Pearce scored for the Tigers (11-15-1), who have lost six in a row.
Hitmen goalie Chris Driedger made 24 saves to improve his record to 14-3-2. Driedger has a personal winning streak of seven straight games.
Marek Langhamer started in net for the Tigers and stopped 16 of the 20 shots he faced before he was relieved by Cam Lanigan at 16:02 of the second period. Lanigan turned aside all seven shots he faced.
The Hitmen went 2-for-7 with the man advantage, while the Tigers scored once on five power-play chances.
Calgary led 1-0 after the first period on a late goal by Rask.
Sylvester then scored a shorthanded goal and a power-play goal in the second period before Padakin scored to put the Hitmen up 4-0.
With the Tigers enjoying a two-man advantage early in the third period, Pearce scored his ninth goal of the season to spoil Driedger’s shutout bid.