The North Division champions find their backs against the wall after another home-ice loss on Saturday.
Dan DeSalvo broke a 1-1 tie with 2:45 remaining in the second period and Cleveland went on to a 5-1 win over Syracuse, taking a 2-0 lead in the best-of-five series.
The Monsters host Game 3 on Tuesday night.
Sonny Milano registered a goal and two assists for Cleveland, which has now won 11 straight playoff games going back to 2016.
Justin Scott, Mark Letestu and Derek Barach also scored, and Brad Thiessen made 18 saves as the Monsters finished with a 32-19 advantage in shots.
Ross Colton scored the only goal for the Crunch, who are quickly facing elimination after putting up the best regular-season record in franchise history.
North Division Semifinals – Series “C” (best-of-5)
N1-Syracuse Crunch vs. N4-Cleveland Monsters
Game 1 – Fri., Apr. 19 – Cleveland 5, SYRACUSE 3 | Recap
Game 2 – Sat., Apr. 20 – Cleveland 5, SYRACUSE 1
Game 3 – Tue., Apr. 23 – Syracuse at Cleveland, 7:30
*Game 4 – Thu., Apr. 25 – Syracuse at Cleveland, 7:00
*Game 5 – Sat., Apr. 27 – Cleveland at Syracuse, 7:00
*if necessary… All times Eastern