But the Hornets (20-2, 5-0), ranked No. 3 in Southern California and tied for No. 2 in the state, scored the final five points of the half in the last 27 seconds and never trailed again.
OCC shot 33.3% from the field, including two of 16 from three-point range (12.5%), and were bested in the rebounding (43-32) and turnover categories (16-15), by the hosts.
Pirates sophomore Samantha Hansen had 24 points, 14 rebounds and made nine of 17 field-goal tries, as well as six of her seven free throws.
But the 6-foot standout got little help from her teammates.
Other than Hansen, the rest of the roster was 10 for 40 from the field and combined for 19 rebounds.
Fullerton freshman Aunjanay Chambers came off the bench to nearly match that contribution, collecting 17 points and 11 rebounds to back a 22-point performance by freshman guard Amanda Frost.
"We just didn't play well enough to win," said Thornton, whose team rallied to within 48-44 with 6:50 left in the game. "There is not much room for error when you play a good team like that, and I don't think Fullerton played particularly well. [The Hornets] gave us a lot of opportunities and we just didn't take advantage.
OCC's biggest struggles came on offense, operating against an athletic lineup that disrupted the Pirates typically crisp execution. On most possessions, the Pirates were relegated to free-lance drives and inside moves by Hansen to produce shots, much less points. Many times OCC's off-balanced shots resembled desperation heaves more typically seen when trying to beat the shot clock.
"There have been times when we've played Fullerton in the past that they've done a good job defensively and taken us out of [our offense], and they are a good defensive team," Thornton said. "But I really didn't think that was the case tonight. I think [the reason for the offensive woes] was more us.