A couple of unearned runs scored on a Jimbo Watson single and an error to extend the lead to 10-1 in the fourth.
Tennessee started with a run in the first on a fielder's choice by Javi Herrera. The Bucs (9-16) then answered with one in the second on a ground out by Davis Burklin that scored Blake Church, who doubled and took third on an error.
ETSU added two more in the eighth on a ground out and an error to cut the lead to 10-3 before Tennessee's Josh Alley tripled home Todd Martin in the bottom of the frame.
Rob Fitzgerald (1-0) picked up the win after pitching four innings. He gave up one unearned run and the only two ETSU hits with two strikeouts.
Fitzgerald, along with relievers Brandon Crowe and Patrick Green, combined to retire 17 straight hitters at one point. Freshman Jack Branston made his debut as he pitched the ninth, striking out two.
Steven Calicutt (2-3) took the loss as he was roughed up for seven runs (six earned) on five hits in 2 1/3 innings. Five Buc pitchers combined for eight walks and nine strikeouts.