James Powell added 17 for the Gauchos (5-2), who hit 9 of 14 3-point shots. Harris and Powell each had four of those 3-pointers.
Harris hit his first 3-pointer nine minutes into the game to give Santa Barbara an 18-15 lead. But then the Gauchos went ice cold and went more than seven minutes without scoring a point. Portland responded to that cold spell with a 15-7 run that gave the Pilots a 30-25 lead late in the first half.
But Harris' 3-pointer at the buzzer cut the Gauchos' deficit to 30-28 at intermission. Santa Barbara took the lead for good when Powell hit a 3-pointer to make it 38-26 with 16 minutes left in the game.
Portland cut its deficit to 42-41 when Ben Sullivan hit a 3-pointer, his only one of the game, with 12:19 left. But the Gauchos answered with six straight points, including a dunk by Harris, to push the lead back to 48-41.
The teams traded baskets for most of the remainder of the game but Santa Barbara's lead continued to grow as the Gauchos hit four 3-pointers in a three-minute span that pushed their lead to 62-53 with 6:05 left.
Portland cut the margin to 68-63 when Sherrard Watson hit a 3-pointer with 1:19 left. Then the Gauchos scored seven of the game's next nine points to put the contest away.
The Pilots were led by Watson and Walter Thompson with 13 points each.