Alcorn State (6-14, 2-5 Southwestern Athletic Conference) trailed 24-23 at halftime and started after intermission with a 9-0 run in less than two minutes and never trailed again.
The Braves scored on their first four possessions with a layup from Devon Brewer, Sterling's dunk and 3-pointer and a 3-point play from Mosby. Alabama A&M (2-17, 2-4) closed to 35-31 with a layup from Julian Walters, another from Arthur Johnson who then followed that with a 3 but the Bulldogs never got closer.
Johnson scored 16 points for Alabama A&M and Walters totaled 11 points, nine assists, six rebounds and three steals. Johnson and Walters combined to make 16 of the Bulldogs' 21 field goals.
Mannion, who recently reclassified and is ESPN's No.11 overall player in the class of 2019, chose Arizona over Marquette.
He'll fit in with Sean Miller's plans for a faster tempo on offense.
The cream of the crop of American high school basketball will congregate in Colorado Springs from Oct. 5-7, as USA Basketball unveils its newly expanded Junior National Team minicamp in collaboration with the NBA, NCAA and NBPA.