Jeanette Pohlen scored 19 points and Kayla Pedersen added 17 to lead No. 3 Stanford to a 78-64 win over Southern California on Friday night.
The victory was the 51st consecutive Pac-10 victory for the Cardinal, giving Stanford a free ride into the semifinals of next month's conference tournament.
Stanford routed the Trojans 95-51 last month, but USC kept it close this time and trailed by only two points at halftime.
The Cardinal (23-2, 14-0 Pac-10) opened the second half with a 12-2 run to take a 50-38 lead, but the run came at a price. Nnemkadi Ogwumike left the game with a sprained right ankle early in the second half. She gave the Cardinal a 48-38 lead with a layup but landed awkwardly and had to be helped off the court.
USC rallied and had a chance to pull within three points when Stanford coach Tara VanDerveer was called for a technical foul, but Jacki Gemelos missed the two free throws and the Trojans lost the ball on the ensuing possession when Lindy La Rocque was called for a travel.
Stanford took it from there, extending its lead with a 21-8 run.
Chiney Ogwumike added 13 points for the Cardinal and Nnemkadi Ogwumike scored 11 before she was injured.
Briana Gilbreath scored 17 points and Stefanie Gilbreath added 16 for USC (15-9, 7-6).
Despite its 17th consecutive victory of the season, the Cardinal might be showing signs of losing focus.
Friday's victory marked the second consecutive game in which Stanford was tested. The Cardinal were coming off a 62-52 victory over Washington, a team that lost by 29 points to Stanford in January.
Things aren't expected to get any easier for the Cardinal, who play at No. 9 UCLA on Sunday. It's unknown if Ogwumike and her 16.6-point average will be able to play against the Bruins.