Bachus was 18-of-32 passing for 245 yards, threw a touchdown pass and ran for a score from 10 yards out to lead the Skyhawks (6-3, 5-1 Ohio Valley Conference), who rebounded from a 17-10 loss at Southeast Missouri that snapped a four-game win streak.
Zerrick Cooper threw a touchdown pass and ran for a score to lead Jacksonville State (6-4, 3-3).
Williams scored with 24 seconds left in the third quarter, but the 2-point conversion failed to give UT Martin a 19-13 lead.
Bryant Wallace's 37-yard field goal pulled the Gamecocks to 19-16, and Ryan Courtright's 18-yard field goal for the Skyhawks capped the scoring with 5:46 remaining.
Jacksonville State crossed midfield on its last two possessions but turned the ball over on downs both times.
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