Mercer's Cole Fisher had just booted a 29-yard field goal for a 23-20 lead. On the Buccaneers' first offensive play in the extra period, Herink connected with Stinson from the 25 to give ETSU (2-2, 1-1) its first Southern Conference win.
ETSU, trailing 20-10 going into the fourth, tied it after JJ Jerman's 49-yard field goal and Blake Rogers' 1-yard run with 4:41 left in regulation.
Herink threw for 284 yards to 12 different receivers, and ran for 34 yards and a touchdown. Stinson hauled in four passes for 60 yards.
Kaelan Riley led Mercer (1-3, 0-2), throwing for 257 yards and one touchdown. CJ James Leggett rushed for 109 yards and a score.
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