Katie Troy and Jacie Rismoen scored four points each in the overtime period to lead the Monarchs to victory.
Troy finished with 17 points and Rismoen had 15 for the Monarchs, who used a 12-2 advantage in the second quarter to take a 19-18 halftime lead.
Troy had eight in the fourth quarter to help Mark Morris force overtime.
“Our seniors really stepped up we we needed them tonight and led us to victory,” Mark Morris coach Sean Atkins said.
Grace Goode led Ridgefield with 18 points. Kelli Krusl had 14 and Courtney Beyer added 13.
MARK MORRIS 54, RIDGEFIELD 53, OT
RIDGEFIELD — Kellie O’Dell-Nguyen 0, Kelli Krsul 14, Josie Rinta 0, Annikka Hill 7, Leilani Starns 0, Courtney Beyer 13, Hailey Braunstein 0, Grace Goode 18, Natalie Andrews 0, Audrey Chapman 1, Emma Thulin 0. Totals 17 (5) 14-20 53.