Trinity (5-1, 1-0) led 41-29 at the half, sparked by 23 first-half points from Andy Bates. Bates finished the game with 39 points - the most by a Tiger player since the 1996 season.
Southwestern, picked to win this year's SCAC Championship, trailed the entire way as Trinity jumped out to a 13-2 lead early in the game. Bates eight of the team's first 11 points, and hit his first 13 shots in a row. He also hit six three-pointers in the first half, finishing with seven for the game.
Southwestern cut it to three at 16-13 with 14:22 left in the first half, but the Tigers went on a 21-3 run to pull ahead by 19 points.
Mitch Walker and Casey Hill both finished with 12 points in the game, and the Tigers shot 47.3% from the field.
Bates, James Lake, and Ross Burt all finished with a team-best four assists, while Jay Riola scored five points to go with six boards.
Jamonn Little led the Pirates with 16 points and six rebounds in the game, while Aaron Bowser finished with nine points. Southwestern shot 40% for the game, but hit just 23.8% (5-21) from three-point range.
Trinity will face Division I Texas A&M University-Corpus Christi next Tuesday at 7:00 p.m. The Tigers return home December 29-30 for the Trinity/Southwestern Holiday Classic.