The Gamecocks (4-2) came from behind twice in the game. Valparaiso had leads of 2-0 and 3-2.
It was 3-3 when JSU batted in the seventh. Chase Silvani doubled, pinch-hitter Paschal Petrongolo tripled him home and after Michael Bishop walked and stole second, Eddie Mora-Loera doubled them both home.Mora-Loera singled home the tying run in the fifth.
The rally made a winner of Michael Mason, the fourth of five JSU pitchers.
Travis Stout picked up a four-out save for his third save of the season. He has not allowed an earned run this season and has given up just one in his last 26 games over the last two seasons.