New York Mills had a balanced attack with Tate Olson and Noah Noffsinger contributing 19 points each, Jack Peeters adding 17 and Jonah Johnson chipping in with 10.
Rothsay was led by Tanner Heier with 10 and Chris Carrillo with 8. Sam Danielson and Karson Jensen each had 7.
New York Mills (17-1) will host Henning on Tuesday night.
Rothsay (5-13) has a home game with Pelican Rapids on Tuesday night.