USC loss in Pac-12 women’s tournament endangers NCAA prospects

USC needed a win or two in the Pacific Life Pac-12 Conference women’s basketball tournament to bolster its slim postseason hopes.

But after a 69-55 loss to Washington State during Thursday’s quarterfinal round at the Galen Center, USC’s chances of making the NCAA tournament were downgraded to hopeless.

Measured by seeding differential, the third-seeded Trojans’ loss to the 11th-seeded Cougars marked the biggest upset in tournament history, besting the 2002 upset by seventh-seeded Oregon against second-seeded Washington.

Washington State (13-19) also became the lowest-seeded team to reach the tournament’s semifinal round, where it will play second-seeded California (23-8) on Friday at Staples Center.

The winner of that game will play the winner of Friday’s other semifinal between top-seeded Stanford (29-1) and fourth-seeded Arizona State (20-10) in Saturday’s championship at Staples Center.

USC, meanwhile, fell to 18-12 and will await announcement of the 64-team NCAA tournament field Monday.

“It’s a longshot,” Coach Michael Cooper said.

Indeed. In each of the past two seasons, USC, which hasn’t advanced to the tournament since 2006, had 19 wins before the field was announced -- and both times, it was excluded.

Cooper said his team won’t accept a WNIT invitation -- “We don’t want to go that route” -- as it did last season, which likely means USC’s season is finished.

The Trojans had twice beaten Washington State in the regular season but trailed by five at halftime Thursday after 11 costly first-half turnovers.

In the second half, Washington State led 30-27 with 18 minutes 51 seconds left, then went on a 16-5 game-deciding run. USC, which had its six-game winning streak ended, got no closer than eight points thereafter.

Washington State was led in scoring by April Cook’s 15 points.

The Trojans shot just 26% and were led by senior forward Briana Gilbreath, who scored 17 and grabbed 10 rebounds.

Stanford 76, Washington 57 -- Stanford led by as many as 27 points against the eighth-seeded Huskies (17-13).

Nnemkadi Ogwumike had 18 points and seven rebounds and sister Chiney had 16 points and 11 rebounds to lead the Cardinal to its 76th consecutive victory against a conference opponent.

The Cardinal held Pac-12 freshman of the year Jazmine Davis to eight points -- only the fourth time this season the Washington guard did not score in double figures.

Arizona State 68, Arizona 53 -- The Sun Devils jumped out to a 16-point halftime lead against the 12th-seeded Wildcats and cruised to their third win this season against their in-state rival.

The Sun Devils had a 21-4 advantage in points off turnovers and a 23-7 edge in bench points to help seal their dominant victory.

Ten players scored for Arizona State, led by forward Kimberly Brandon’s 15 points.

Arizona (15-17) was led by Davellyn Whyte’s 17 points.

California 68, Colorado 59 — The second-seeded Golden Bears staved off a potential comeback by the 10th-seeded Buffaloes.

Cal (23-8) led by 16 in the first half, but Colorado cut the margin to eight by halftime. In the second half, the Buffaloes (18-13) came to within six in the final minutes, but couldn’t close that gap.

Four players scored in double figures for California, led by forward Layshia Clarendon’s 12 points.

Brittany Wilson had 18 points to lead Colorado.

baxter.holmes@latimes.com

twitter.com/baxterholmes