The three-game Conference USA series continues Saturday with the final game on Sunday.
Poston hit a two-run homer in the fourth inning to give UTSA a 7-1 lead.
Bailey, UTSA’s home run leader on the season, hit a solo shot in the third inning that made it 5-1.
Bailey finished the game with three hits. Jonathan Tapia had three hits, a walk, three RBIs and scored four runs.
UTSA starter Luke Malone pitched 5 1/3 innings and improved his record to 6-1. He allowed six hits with five strikeouts, no walks and no earned runs.
