The Flames carried a 2-1 lead into the third period before scoring three in 1:54 - including two by Elias Lindholm only 19 seconds apart - to secure one of their most important W's of the season.
Lindholm added an assist for a team-leading three-point night.
Earlier in the day, the Flames recalled Dennis Gilbert from the AHL's Calgary Wranglers. Gilbert drew into the lineup, with Head Coach Darryl Sutter electing to play seven defenceman and 11 forwards. Brett Ritchie, Matthew Phillips and Radim Zohorna (non-COVID illness) were the scratches up front.
The decision paid off, with Milan Lucic getting some additional ice time and scoring a pivotal goal in a 1-1 game with a clapper in the second period.
Tyler Toffoli and Dillon Dube rounded out the offence, while Jacob Markstrom - who played in his 400th career game - made 24 saves
The Flames were far and away the better team in the early going, and at 7:13 - after building a 4-1 lead on the shot clock - they were rewarded for their relentless pressure on the forecheck.
Sharks blueliner Jaycob Megna coughed up the puck in the middle of the ice, giving Toffoli a free look from between the hash marks. With a quick flick of the wrist, the Flames had a 1-0 lead on Toffoli's team-leading 11th, after beating Kaapo Kahkonen clean past the glove.
A tripping penalty to Adam Ruzicka gave the homeside life with the game's first powerplay, and the league's 19th-ranked unit made short work of it. Erik Karlsson - who's been on a tear this year and looking more like the elite D man of old - whipped a beautiful diagonal pass through a seam and connecting with Timo Meier for the one-timer below the right circle.
1-1, five seconds into the advantage.
Shots on goal favoured the Flames 10-3 after one, but that told only part of the story. The visitors had a number of golden opportunities and could have blown this one wide open, but were just off the mark. The line of Jonathan Huberdeau, Nazem Kadri and Andrew Mangiapane had four scoring chances, including a 3-on-1 in the opening minutes, followed by a breakaway that No. 88 struck iron on late in the frame.
In all, the Flames had a wide edge in play, leading to an 11-2 lead in chances, including a 4-1 advantage from the high-danger areas.
The Flames kept up the pressure in the second and took a 2-1 at 6:01 when Lucic tallied his first of the season. With Ritchie out and the Flames dressing seven defenceman, Lucic and Trevor Lewis played with a number of different forwards all night. On this play, it was Lindholm in the middle, and the pivot made a dandy pass into the high slot that the big man slapped home.
The puck caromed in off the thigh of Karlsson in front, but they all count - and the emotional celebration from both Lucic and his teammates and in the pile after said it all about what that moment meant to the group.