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.
Forward Kennedy Meeks, who has averaged 9.4 points and 6.5 rebounds at North Carolina, has pulled out of the NBA draft and will return to the Tar Heels.
Cal big man Ivan Rabb could have been selected in the top 10 of the NBA draft. Instead, he's returning to Berkeley to make himself, and the Golden Bears, stronger.
Devin Williams' decision last month to sign with an agent and enter the NBA draft has left West Virginia in a tough spot.