The Cougars improved to 8-1 overall, 5-1 in the county. The Wildcats fell to 4-4, 4-2.
Jen Reilly registered an assist for Chesapeake, while goalkeeper Casey Smith tallied six saves on the nine shots she faced.
Arundel goalkeeper Kara Grosbach had nine saves.
The Cougars will be back in action Tuesday when they visit South River while the Wildcats will host Glen Burnie.