LOS ANGELES -- Alanna Smith lost the nail on her right index finger in the opening minutes Sunday.
When it came time for a clutch layup, she went with her left hand instead.
The Stanford senior drove the lane and made a layup with three second to lift the No. 10 Cardinal over USC 69-67.
Smith finished with 23 points and 12 rebounds as Stanford (21-4, 11-3 Pac-12) rallied from 15 points down to defeat the Trojans (15-10, 5-9).
"We just found a way to win," Stanford coach Tara VanDerveer said. "I'm really proud of the way our team battled. Everyone just tried to focus on what we needed them to do. We didn't shoot for a great percentage. We made free throws down the stretch."
After Stanford regained the lead with 6:39 to play, the final minutes were frantic with nine lead changes and six ties.
"It's a hard loss because we could have won the game," USC coach Mark Trakh said. "They did what they had to do at the end to win it. There are no excuses. They were the better team today and they beat us."
The Trojans (15-10, 5-9) were led by the Moore sisters. Minyon Moore had 18 points, 10 rebounds and eight assists, and Mariya Moore added 14 points.
Stanford shot just 37.1 percent but out-rebounded USC 45-33 with 17 offensive rebounds.
"I think we played really good defense," Trakh said. "It went down to the wire but offensive rebounds were killing us. That was basically the game."
DiJonai Carrington added 18 points and 12 rebounds for Stanford, and Kiana Williams played all 40 minutes and had 16 points and four assists.
"That was a battle," VanDerveer said. "Extremely physical. I thought our team showed a lot of grit. We stayed with things really well. It was tough. Made some big plays."
The Cardinal aggressively went to the basket in the final period. They shot 14 free throws, making 11.
Carrington and Williams each scored seven of their points in the fourth period, when Smith scored 12 of her 23.
"Nothing was really going right," VanDerveer said. "We got back and then they made another run, and then we got back again. We just kept getting off the mat. They really showed great fight.
"Our big three stepped up and made some big plays."
USC received a scare when guard Minyon Moore went down hard after fast-break layup with 5:28 left in the second period. She remained on the floor for several minutes before heading to the trainer's room but returned to play at the 3:43 mark.
"Minyon was a warrior," Trakh said. "Got a double-double and just played her butt off. Ten rebounds against a bunch of trees? She did a great job."
Stanford: After winning eight consecutive games, the Cardinal had gone 3-3 in their last six while struggling from the 3-point line. They were good on 7 of 25 3-point attempts Sunday but hit three consecutive to regain the lead in the final period.
USC: The Trojans are 1-7 against teams they played while ranked in the AP Top 25.
Stanford: Returns home to play Arizona on Friday.
USC: Hits the road on Friday to play No. 9 Oregon State.
More AP college basketball: https://apnews.com/Collegebasketball and https://twitter.com/AP—Top25