PULLMAN, Wash. (AP) _ Chad Morton ran for three touchdowns Saturday night as Southern California snapped a five-game losing streak with a 31-28 victory over Washington State.

Southern Cal (4-6, 2-5 Pac-10) improved to 50-6-4 against the Cougars since 1921, their best winning percentage against any conference team.

Washington State (2-8, 1-6) lost its fourth straight and fell into last place in the Pac-10.

This was the first November football game ever in Pullman that started with temperatures in the 60s.

The game was close in the first half, but two quick touchdowns by Southern Cal to open the third quarter provided the winning points.

Morton rushed 29 times for 117 yards, while quarterback John Fox was 12-of-22 for 117 yards.

The Trojans scored on their first possession when Morton carried two defenders into the end zone on a 7-yard run.

Washington State responded with a 73-yard drive that was capped by Deon Burnett's 22-yard burst up the middle. Burnett finished with 96 yards.

Then Southern Cal marched 80 yards, including a 42-yard pass from Fox to R. Jay Soward. Morton's 3-yard run lifted Southern Cal to a 14-7 lead.

Morton's 18-yard run set up David Newbury's 34-yard field goal early in the second quarter.

After its offense stalled on four straight drives, Washington State pulled out a trick play. Quarterback Steve Birnbaum threw a backfield pass to receiver Collin Henderson, who fired a 24-yard touchdown pass to a wide-open Marcus Williams to make it 17-14 at halftime.

Birnbaum was 24-of-42 for 284 yards and two touchdowns. Williams caught seven passes for 121 yards.

The Trojans opened the third quarter with a 92-yard drive, including a 37-yard bootleg by Fox. Morton rushed three times for the final 22 yards, scoring on a 1-yard burst for a 24-14 lead.

After a bobbled kickoff return buried the Cougars on their own 4, Birnbaum was pressured in the end zone and threw the ball just as he was hit. Cornerback Kris Richard grabbed the wobbly pass at the 6-yard line and scored easily for a 31-14 lead.

The Cougars replied with an 80-yard drive _ kept alive by a key roughing-the-passer penalty on third-and-10 _ that ended on a 5-yard touchdown pass from Birnbaum to Nian Taylor.

Birnbaum's 5-yard touchdown pass to Taylor with 2:14 left narrowed USC's lead to 31-28 but the Trojans recovered the onsides kick and kept the ball until punting with just 13 seconds left.