MOBILE, Ala. — Daniel Milliman had a shutout into the sixth inning and Travis Sibley had two hits and four RBIs as second-seeded UT Arlington opened the Sun Belt Conference baseball tournament with a dominating 8-4 victory over host South Alabama on Wednesday.UTA (31-25) advances to play No. 6 seed Troy at 7:30 p.m. Thursday in the double-elimination tournament. Troy (25-30) upset third-seeded Arkansas State 4-3 in 13 innings in another opening-day matchup.Top seed Louisiana Lafayette, ranked as high as second in some national polls, beat Louisiana Monroe 8-3 and fourth-seeded Texas State defeated fifth-seed Western Kentucky 4-5 in 10 innings in the other games.Milliman, a senior out of Fort Worth Southwest High School, improved to 6-0 this season as he allowed five hits, walked five and struck out three in 5 2/3 innings. He allowed three runs, but none earned.South Alabama (22-32) scored three times with two out in the sixth as relief pitcher Chase Weaver allowed a run-scoring single and a two-RBI double. All three runs were charged to Milliman, who had walked two in the inning before leaving, but were unearned because of an error by Sibley.UTA opened the scoring with RBI doubles from John Michael Twichell in the second and Matt Shortall in the third. Sibley gave the Mavericks some breathing room in the fourth with a run-scoring single and then a bases-loaded double in the fifth that scored three.Thursday’s tournament schedule begins at 9 a.m. with Western Kentucky against UL Monroe, Arkansas State plays South Alabama at 12:30 p.m., UL Lafayette meets Texas State at 4 p.m. while Troy and UTA start the day’s final game at 7:30 p.m.