Marcus Johnson scored a career-high 15 points for Samford (7-8), shooting 5-of-5 from the field - including three 3-pointers - and 2-of-2 from the free throw line. Tyler Hood added 11 and Darius Jones-Gibson 10.
The Bulldogs trailed 13-12 before 3-pointers by Roberts both sparked and capped a 25-5 run, which gave Samford a 37-18 lead with 3:30 left in the first half.
Auburn-Montgomery trailed by at least 14 the rest of the way, and by as many as 40 in the second half.
Samford made 13 of 26 3-pointers, shot 52 percent overall and recorded a season-high 24 assists.
Tristen Harrell led Auburn-Montgomery, which committed 21 turnovers, with 21 points.