Sam Houston (13-9, SLC 6-2) totaled 15 hits while Texas State (14-8, SLC 4-4) was limited to nine.
Right fielder Jake Arrington started a three-run second inning with a single to left field then moved to third on a single by first baseman Ryan O'Hearn. Arrington scored on a throwing error after a bunt attempt by catcher John Hale. Second baseman Jessie Plumee and shortstop Corey Toups each singled to score two more runs.
An inning later, the Bearkats added three more runs on an RBI double by third baseman Kevin Miller, a run-scoring single by Plumlee and the Bobcats' third error of the game.
Texas State got on the scoreboard with a three-run sixth inning with a two-run single by center fielder Jeff McVaney and an RBI single by designated hitter Ben McElroy.
Plumlee's sacrifice fly and a two-run single by left fielder Luke Plucheck increased the Bearkat lead to 9-3 in the bottom of the seventh inning. Hale picked up another RBI in the bottom of the eighth with a single.
Bearkat starter and game winner Justin Jackson (3-2) held Texas State to on hit in the first five innings before leaving in the sixth inning. Michael Oros, Jordan Bunch and Michael Burchett pitched in relief.
Colton Turner (1-1) took the loss, giving up eight hits and six runs in two and two thirds innings.
Sam Houston, winners in the first two games of the series, will play host to Texas State in the final game Sunday at 1 p.m.