The Bruins made 30 of 40 free throw attempts, including 8 of 10 in the final 39 seconds. Johnson made 16 of 19 from the line, including 6 of 8 in the last three minutes of the game. Belmont went the final 4:25 without a field goal.
Ian Clark added 17 points and Scott Saunders had 12 for the Bruins (5-2, 2-0 Atlantic Sun Conference), who have won five games in a row and four straight in the series.
Mercer battled back from a 44-33 halftime deficit to tie the game twice in the second half, but never took the lead. The Bears (5-3, 1-1) made 21 of 23 free throw attempts.
Langston Hall scored 23 points, Daniel Coursey added 18 and Jakob Gollon had 17 for the Bears.