Williams made four 3-pointers and nine of Harris' points came from the stripe and the Titans (4-7) shot 54.4 percent from the field.
Aaric Murray had 21 points and grabbed 12 rebounds for Texas Southern (3-7). Forty-five rebounds, 22 on the offensive end, helped Texas Southern stay close -- despite shooting 39 percent.
After not making a 3-pointer in the first half, Cal State Fullerton made three in a span of 2:17 and took a 65-56 lead. Texas Southern scored the next eight to make it a one-point game. But Williams' 3-pointers started a 9-0 CS Fullerton run for its first double-digit lead of the game at 74-64 with 4:51 left.
Cal State Fullerton made 7 of 8 free throws in the final minute to secure the victory.
The second annual Gavitt Tipoff Games, eight games between members of the Big East and Big Ten to be played Nov. 14-18, will feature Villanova at Purdue in the opener.
Michael Lewis is leaving his assistant coaching job at Butler to take the same position at Nebraska under Tim Miles.
College basketball fans should be excited about next season's Jimmy V Classic, an event that will feature Duke's heralded freshman class.