The Monsters rallied with three goals in the third period to beat host Toronto, 4-2, on Jan. 5.
The Marlies took a 2-1 lead with a goal early in the third period.
The Monsters’ Cameron Butler tied the game at 2-2, and Rocco Grimaldi gave Cleveland the lead on goal with 4:42 remaining.
Dylan Gambrell added an empty-net goal for the final margin.
Gavin Brindley scored the Monsters’ first goal in the second period.
Jet Greaves made 32 saves, a day after a 33-save effort.
Cleveland (20-10-1-3) swept both games in the weekend series.
The Monsters are off until Jan. 10, when they welcome Laval to Rocket Mortage FieldHouse.