UCLA, 14-7 overall and 5-5 in the Pac-10, was led by 20 points from Doreena Campbell.
The Trojans (12-9, 6-4) shot 47% in the first half, compared to UCLA's 22%, and had a 46-25 lead at the break.
Down by 21 points, the Bruins faced a major uphill climb but got off to a good start in the second half by scoring the first six points and using a 10-3 run to cut the lead to 14 at 49-35. Campbell scored eight of the 10 points in the run.
The Bruins closed the gap to 10 points, 55-45, after consecutive jumpers by Erica Tukiainen, Campbell and Atonye Nyingifa. USC, however, got the lead back up to 19, 68-49, with an 11-2 run.
Campbell had her fourth 20-point game of the season. Tukiainen had 14 points and a career-high four steals, and Nyingifa added a career-high tying 10 points and eight rebounds.
UCLA junior center Moniquee Alexander was the game's leading rebounder with a career-high 13 boards, seven offensive. She also tied her career best with two blocks and scored eight points.
LeNoir's total moved the senior guard into the No. 13 in all-time USC career scoring, and with her three assists LeNoir tied Trojans great Cheryl Miller at No. 5 in career assists.
The Trojans finished the game shooting 48.4%, and UCLA ended at 38.5%.