Gennifer Brandon, Brittany Boyd and Layshia Clarendon scored 14 points each as No. 6 Cal beat No. 15 UCLA 79-51 Friday night in Los Angeles.
Reshanda Gray added 10 to lead the Bears (22-2, 12-1 Pac-12) to their 10th straight win.
Atonye Nyingifa scored 20 points for UCLA (19-5, 10-3 Pac-12), which had won six straight since a loss at California on Jan. 20.
The Bruins also took their first home loss in conference play this season
Cal hasn't lost since a defeat to No. 4 Stanford on Jan. 8.
"We knew this was a big game coming in," Cal coach Lindsay Gottlieb said. "As a coaching staff you try to prepare them the best you can, and give good scouting to give them confidence. But what's really special is when they take that message and rise above."
The Bears built a 19-point lead in the first half and led by 18 at the break.
UCLA made an early run in the second half. Nirra Fields made a steal and dribbled the length of the court to score and pull the Bruins to 47-36 with 13:57 remaining, but they could get no closer the rest of the way.
UCLA shot just 33.3 percent (19 for 57) from the field.
The Bruins started slowly, missing their first five field-goal
UCLA pulled to 11-10 after an outside shot by Kacy Swain, but the Bruins' poor shooting in the first half cost them.
Stanford 79, USC 55: Chiney Ogwumike had 26 points and 15 rebounds for her record-setting 20th double-double of the season, and the No. 4 Cardinal defeated the host Trojans for the 12th straight time.
Joslyn Tinkle added 17 points and 11 rebounds, Mikaela Ruef had a career-best 12 points and eight rebounds, and Amber Orrange had 10 points to help keep the Cardinal (23-2, 12-1 Pac-12) tied with Cal atop the league standings.
Stanford earned its ninth straight victory and improved to 14-0 away from home this season.
USC (8-16, 5-8) has dropped five in a row and eight of nine.