The former Lake Forest El Toro standout, who has averaged 20.1 points against USC in her career, was again the central figure in No. 25 Washington's 64-63 victory over USC in a Pac-10 tournament quarterfinal game Saturday.
Mendiola, the conference's player of the year, scored 29 points and made a 12-foot shot with 33 seconds left to put the Huskies (22-6) ahead for good at 62-61.
"Giuliana was the glue for us," Washington Coach June Daugherty said. "She kept hitting big shots and kept us going."
USC, which trailed, 32-27 at halftime, tried to set up for the last shot. But a pass from Rometra Craig to Rachel Woodward went awry with nine seconds to play. The Huskies, led by Mendiola, collapsed on Woodward and tied her up. The possession arrow was pointed Washington's way and the Huskies had the ball.
The Trojans fouled Laurie Payne with 8.4 seconds left, and the senior forward made both free throws. That negated a layup by USC forward Meghan Gnekow as time ran out.
Ebony Hoffman led USC (14-17) with 19 points and nine rebounds.
"A very disappointing loss," said USC Coach Chris Gobrecht. "I thought it was a game we should have won and a game I thought we had."