Richmond went cold at the worst possible time, blowing a seven-point lead late in the second half and falling at Massachusetts, 70-65.
The Spiders (13-8, 3-3 in the Atlantic 10) had a 63-56 lead with 6:02 to play, but allowed 11 straight points and didn't score again until Kendall Anthony knocked down a pair of free throws with 16 seconds to play.
That brought Richmond to within 67-65, but Chaz Williams made both free throws on the other end and when Anthony missed 3-point attempt, Richmond's comeback bid was over.
Williams scored 18 points to lead the Minutemen (13-5, 3-2). He also added six rebounds, five assists and three steals. Cade Lalanne had 12 points off the bench, and Sampson Carter finished with 10.
Wayne Sparrow scored 13 off the bench to lead Richmond, which had a hard time finding its offensive rhythm. The Spiders entered the day first in the Atlantic 10 making 8.5 3-pointers per game, but against the Minutemen went 8-for-25 from beyond the arc, missing their last six attempts.
The Minutemen led 34-29 at the end of a choppy first half that saw the teams combine for 21 fouls. Five Spiders had two fouls apiece at intermission. The Minutemen's Terrell Vinson played just 20 minutes before fouling out, and Anthony fouled out for Richmond in the final seconds.