Trailing 63-56, Williams hit a 3-pointer with 5:52 left to spark an 11-0 run. Kendall Anthony hit two free throws with 16 seconds left—the Spiders’ first points in 5:46—to make it 67-65. Williams made two free throws 2 seconds later, then clinched the win with a foul shot with 1 second remaining.
Cady Lalanne added 12 points and Sampson Carter 10 for the Minutemen (13-5, 3-2), who led the entire first half en route to a 34-29 advantage at the break.
The Spiders took their first lead at 37-36.
Wayne Sparrow scored 13 points and Cedrick Lindsay 12 to lead Richmond (13-8, 3-3), which entered on a two-game winning streak after defeating No. 19 Virginia Commonwealth 86-74 in overtime.