The Great Danes (11-3) never trailed after Iati's first of two 3-pointers in a span of less than a minute gave them a 28-25 lead with 15:18 remaining.
The Bears (4-7) stayed close, never falling behind by more than eight the rest of the way, then got within a point, 49-48, at the 3-minute mark after a 3-pointer and a layup by Tucker Halpern.
Black made 1 of 2 free throws and Devlin a pair to make it 52-48. After another Halpern layup, Devlin hit two more and Black another pair for a 56-50 lead with 38 seconds left.
Devlin finished with 15 points and Black 14.
Halpern scored 18 points and Matt Sullivan 16 for Brown.
Shooting guard Jaylen Nowell, ranked No. 45 in the ESPN 100, chose the Washington Huskies on Wednesday over California. As a junior he led Garfield Heights to a state championship and was named MVP of the tournament.
Donnie Tyndall is appealing the 10-year show-cause penalty that was handed down by the NCAA in April for violations stemming from his time as men's basketball coach at Southern Mississippi.
Top-50 prospect Jaylen Nowell committed to Washington on Wednesday. Nowell, a shooting guard, is No. 45 on the ESPN 100.