LOS ANGELES -- It wasn't pretty, but Oklahoma State's run of nonconference dominance remains intact.
Liz Donohoe scored 21 points, Roshunda Johnson added 17 more and the No. 19 Cowgirls rallied in the second half to beat Southern California 66-62 on Sunday.
Oklahoma State (9-1) improved to 76-1 against nonconference opponents over the last eight seasons with the comeback victory. USC (8-3) led the entire way until the 11:58 mark of the second half, when Donohoe and Johnson keyed a 13-0 Cowgirls run that put them in front for good.
"A lot of times we're not a pretty team, but we keep plugging away and finding a way to win," OSU coach Jim Littell said. "I'm very proud of our team. This was a gutsy performance."
Donohoe shot 7 of 9 from the floor and had eight rebounds while Johnson shot 8 of 16 and had five assists for the Cowgirls, who won their seventh straight.
USC opened the game with an 11-2 run and held off multiple OSU surges to take a 31-25 lead into halftime, but OSU chipped away and pulled into its first tie when Donohoe nailed a 3-pointer from the left wing to make it 42-42 with 11:58 to play.
Johnson followed with a jumper from the free throw line to give the Cowgirls their first lead of the game at the 11:36 mark, sank another basket to extend the lead and then Donohoe hit a short jumper to cap a 13-0 run and give OSU a 48-42 lead with nine minutes to play.
"We haven't shown anybody how good we can play yet," said Donohoe, a senior forward. "We made a bunch of mistakes in this game but this shows we have overcome some those things."
Donohoe was clutch late, hitting a 3-pointer after USC had pulled within 59-57 and sinking a pair of free throws with just over a minute left for what turned out to be the winning points.
"Liz has been through this before," Littell said. "She's started every game of her career and you expect people who have been through battles to step up and make plays with the game on the line and she did."
Alexyz Vaioletama scored 20 to lead the Trojans, who saw their three-game win streak snapped in their final nonconference game. Brianna Barrett added 11 points but missed two free throws with a chance to tie it late.
"We got a little too comfortable as far as the score and the way we played," Vaioletama said. "We didn't knock down our shots and the intensity level went down. They wanted it more."
Vaioletama's 3-pointer with just under a minute left cut USC's deficit to 64-62, and Barrett stepped to the free throw line for two shots and a chance to tie it with 16.8 seconds to play.
She missed both, and OSU's Brittany Atkins came down with the rebound to set up a fastbreak layup by LaShawn Jones to essentially end it.
"At halftime coach talked about us needing to pick it up, and that's what we did," Donohoe said. "We had a good energy, a good atmosphere, and we just fed off of that."
Oklahoma State: The Cowgirls improved to 3-1 all-time against USC . They won despite 19 turnovers . Donohoe, Atkins and Brittney Martin each had eight rebounds.
USC: The Trojans shot just 3 of 11 from 3-point range . They were outrebounded 37-27 . This was USC's first home loss of the season.
Oklahoma State hosts Northwestern State on Dec. 29.
USC hosts UCLA on Dec. 30.