Brandon Slocum also scored 23 points for Moyers, which finished its season at 27-4 after making its first appearance in the state tournament.
Moyers had a 46-40 lead with 2:06 remaining in the third period but Big Pasture rallied to tie the game, 48-48 after the third quarter as Smith scored the final two buckets of the period.
Big Pasture scored 11 consecutive points over a three-minute span of the third period and the opening 2:07 of fourth quarter.
The Rangers had their biggest lead of 58-49 with 5:20 left on a three-point basket by Cox.
Dudley then scored seven straight points to cut the lead to 58-56 and his three-point basket with 29 seconds left tied the game 64-64, setting up Smith’s heroics at the end of the game.
Big Pasture is now 28-1 on the season and will meet Arnett in the semifinals on Friday at 9 a.m. at State Fair Arena.