A close contest from the beginning, Seattle U tied the game at two on a layup by Kacie Sowell (Ventura, Calif.) as 17:26, and took their first lead, 6-5, at 15:50 as Sowell went 1-for-2 from the line.
The Redhawks gained a three-point lead three different times over the next three minutes before the Titans regained the lead, 14-12, at 11:04 on a three-pointer by Samantha Logan.
Alexis Montgomery (Beaverton, Ore.) drove in a layup to re-tie the score, 14-14, at 9:39, but Cal State Fullerton would go on a 8-0 run to lead, 22-14, by the under-eight media timeout.
Ashley Ward (Irvine, Calif.) added a pair of free throws at 6:23 while Taelor Ross (Vancouver, Wash.) and Sowell added layups, but the Titans would lead by as many as 12, 34-22, with just over two minutes remaining on a three-pointer by Chante Miles.
Layups by Ward and Sowell cut the deficit to single digits, 34-26, with 1:14 left before the half but Hailey King hit a three to put the Titans ahead by 11, 37-26, at the half.
Ward opened up the second half with a pair of free throws and Ross cut the deficit to seven, 39-32, with back-to-back layups. Kathleen Iwuoha increased the Fullerton lead to nine, 41-32, near the 18-minute mark before nearly three scoreless minutes for either team.
Miles drove in a layup to put the Titans ahead by double digits once again, but Sylvia hit a clutch three-pointer to jumpstart a 9-0 Redhawks run as they came within just two, 43-41, at 12:16.
Alex Thomas and Wilma Afunugo (Plano, Texas) traded baskets before Shephard hit a three at the seven-minute mark to put the Redhawks ahead by one, 46-45.
Ward hit a jump shot to extend the lead to three, 48-45, at 5:43, but Thomas answered with her own three to tie the game at 48. Ward tied the game once more at 50 on a pair of free throws at 2:46, but Natalie Williams and King would re-extend the Titan lead to four, 54-50, at 2:08.
Trading free throws over the final two minutes, Sylvia Shephard (Alta Loma, Calif.) went 3-for-6 from the line down the stretch. King went 1-for-2 from the line with seven seconds remaining as Cal State Fullerton came away with the win, 55-53.
Shephard led all players with 15 points, recording a double-double, adding a game-high 10 rebounds. Ward scored 10 points for the Redhawks, while Thomas and Williams led the Titans with 13 points apiece. Seattle U outrebounded Cal State Fullerton, 47-38, as a team.
Seattle U (5-7) has a full week off for the Christmas holiday before traveling back to California for a single game at UC Santa Barbara to wrap up the non-conference schedule. The Redhawks open the conference season on the road at Chicago State (Jan. 2) and Kansas City (Jan. 4) before returning home for their Western Athletic Conference home opener on Jan. 9.