Seattle jumped to a 16-9 lead early in the first half and had a 41-31 advantage at the break.
Reese Holliday sank back-to-back 3-pointers early in the second half to bring UMKC to within seven points, 46-39, but Umipig answered with a pair of 3s to spark a 9-4 run to give the Redhawks a 55-43 lead with 12:09 to play. A jumper by Umipig, a tip-in by Powell and 3-pointer by Emerson Murray in the final two minutes sealed the win for Seattle, which shot 53.6 percent from the field.
Holliday led the Kangaroos (11-16, 6-4) with 17 points. UMKC was outrebounded 31-22.