LOS ANGELES -- Southern California stayed close early against No. 4 Stanford, holding Pac-12 leading scorer Chiney Ogwumike to eight points in the first half.

But Ogwumike and Joslyn Tinkle proved too much in the low post in the second half as USC lost to the Cardinal for the 12th straight time, 79-55 on Friday night.

Alexyz Vaioletama scored 14 points and Cassie Harberts added 13 for the Trojans (8-16, 5-8), who have dropped five in a row and eight of nine. They shot 33 percent from the floor and went 13 of 17 from the free throw line.

"The first half we had a good game plan keeping Chiney contained, especially in the low post," Vaioletama said. "The second half it was pretty difficult."

Opening a stretch of four straight games against ranked opponents, USC came out aggressively. There were five lead changes and two ties in the first half before Stanford pulled away over the final 4:58.

Stanford outscored USC 12-2 to end the first half leading 31-19, the Cardinal's first double-digit lead of the game.

The Trojans pulled to 19-17 on a 3-pointer by Ariya Crook before Amber Orrange sparked the Cardinal's run with eight points.

Both teams committed eight turnovers each, but Stanford shot 46 percent from the field to USC's 27 percent.

"They stepped up their tempo offensively," USC coach Michael Cooper said. "We know we have to rebound to play with the top teams in the country."

Ogwumike finished with 26 points and 15 rebounds for her record-setting 20th double-double of the season, and Tinkle added 17 points and 11 rebounds to help keep the Cardinal (23-2, 12-1 Pac-12) tied with No. 6 California atop the league standings. The Golden Bears beat 15th-ranked UCLA 79-51 earlier Friday. Stanford earned its ninth straight victory and improved to 14-0 away from home this season.

Ogwumike scored Stanford's first seven points of the second half before Sara James and Tinkle hit back-to-back 3-pointers that pushed the lead to 44-29.

"They picked up their intensity and got up in our face," Harberts said. "We didn't respond and stayed at the same level."

Tinkle, Mikaela Ruef and Ogwumike combined for a 20-10 run that extended Stanford's lead to 64-39. Tinkle had nine points, Ruef six and Ogwumike four. Tinkle helped the Cardinal to a 36-16 edge in the paint and a 46-33 edge on the boards.

USC managed to end Stanford's streak of holding its previous three opponents to under 50 points. The Trojans shot 31 percent from 3-point range, better than the nation-leading 24 percent that Stanford had been allowing from behind the arc.

The win completed a season sweep by Stanford, which beat USC 75-66 last month. The Trojans haven't beaten the Cardinal since a 73-72 win on Jan. 6, 2008.

"This season has been really difficult," Vaioletama said. "We come into every game like we having nothing to lose, like we can be the team to ruin everybody's season."