The game was tied twice, before the Black Bears took the lead for good in the sixth inning.
Maddie Decker opened the scoring for Maine in the third inning with a three-run home run to center field, to make the score 3-3.
They tied the game again in the sixth inning after Brianna Neely stole second, and Holy Cross catcher Erin Bengston over threw second base, scoring one run.
It was another error that sealed the win for Maine, after Kya Enos hit a triple to right field, Enos scored from third on an errant throw by the right fielder.
The Crusaders won the second game, 3-2, and Maine will face Albany on Friday for their home conference opener.