The Lady Wildcats held a 39-26 second half advantage over the team from Boone County in far eastern Kentucky.
Trigg had its best night of the year at the free throw line, making all eight attempts in the final minute.
Morgan Parker scored 14 for Trigg and was named Player of the Game.
Trigg was set to play McLean County in the second round of the tournament Tuesday (results unavailable at press time). The championship game will be played at 6 p.m. Wednesday.