Willmar had a 31-24 advantage on the boards and the Cards were able to make their free throws down the stretch to create some separation on the scoreboard.
Ellie Colbeck led the Otters with 21 points and 6 rebounds, Karley Braeger had 8 points and Ainsley Hansen led the team with 9 rebounds.
Fergus Falls (8-4, 5-1 CLC) suffered their first conference loss of the season. They will face Perham on Saturday night at 7:15pm at The Hive.