Monett led 16-14 after the first period but trailed 25-18 at halftime.
The Cubs roared out of the locker room and opened the third period with a 9-2 spurt to tie the score at 27-27 with 4:27 to play in the third. Ruskin responded with a 15-0 run to ice the game.
Scoring for Monett were: Kyle Woods, 15; Tyler Green, 11; Travis Thompson, 6; Aaron Patton, 4; and Jarred Witt and Jacob Fair, 2 each.
The Cubs travel to Mt. Vernon on Friday. Game time is set for 6 p.m.