Andrew Mangiapane (2), Chris Tanev, Blake Coleman and Mikael Backlund supplied the offence, while Markstrom stopped 28 shots, as the Flames knocked off the Rangers 5-1 to win their third straight.
Trailing by two entering the third period, the Rangers pulled to within one and the raucous New York crowd turned up the volume - but the Flames were unfazed and pulled away with a trey of unanswered markers to secure the two points.
Elias Lindholm had the first good chance of the game when he and his linemates, Matthew Tkachuk and Johnny Gaudreau, were buzzing in the Rangers' end of the rink for a good half-minute. Lindholm corralled a loose puck between the hashmarks and rifled a quick shot labelled for the far corner, but Igor Shesterkin got his left pad on it and calmly steered the rebound into the corner.
The Rangers turned up the heat on the next shift and nearly had the game's opening tally when Artemi Panarin took a long stretch pass and went in alone on a breakaway, but Markstrom stood tall and coolly punched away the sniper's hard, blocker-side offering.
Otherwise, the Flames were in full control for much of the opening frame, dictating the pace and generating a number of Grade-A scoring opportunities.
A point-blank chance by Oliver Kylington, and another by Sean Monahan immediately after, allowed the Flames to build up a 14-7 edge on the shot clock, as the ice tilted even further in favour of the good guys.
Finally, the dam broke.
And from an unlikely source, no less.
Jumping up in the rush during a brief period of 4-on-4, Tanev took a beautiful feed from Gaudreau and buried a wrister from the right circle, putting the Flames up 1-0 at 18:50.
Elias Lindholm picked up the other assist.