The only goal scored came on an own goal in the 78th minute when a cross from Bruin forward Kara Lang was mis-hit by a USC defender and the ball slipped past goalkeeper Brittany Cameron.
"This is the NCAA Tournament and nothing is going to be easy and nothing is going to be handed to you," said UCLA coach Jillian Ellis. "To be able to win and not play as well as we can play -- we have to take that as a positive. Good teams find a way to win. San Diego certainly didn't make it easy for us."