Down 58-57 with 42 seconds to play, Justin Griner sank a 3-pointer to give Lafayette a two-point lead. North Sand Mountain couldn't convert on either of its remaining possessions, and Lafayette's Cordeski Floyd and Trevond Barnes each made two foul shots to secure the win.
North Sand Mountain led 45-38 going into the final quarter.
Damian Paige had 16 points, six rebounds and three blocks to lead Lafayette (19-11), which will face either Lanett or Westbrook Christian on Thursday at 4:45 p.m. For North Sand Mountain (21-11), Tyler Vann had 21 points, five rebounds and three assists.
Sports Editor Mark Edwards: 256-235-3575. On Twitter @MarkSportsStar.