And WSU took advantage.
Motum, who scored a career-high 34 points in Saturday's loss at Arizona State, followed that with 26 points against USC. He also converted 9 of 11 field goals and had eight rebounds.
"He was very efficient," WSU coach Ken Bone said during a postgame radio interview. "It's the same old deal with him. He just continues to play good basketball."
The Cougars shot 47.6 percent from the field and also made 14 of 19 free throws. But a more efficient offensive performance outside of Motum might have resulted in a blowout as WSU turned the ball over 13 times.
Without senior guard Faisal Aden, who suffered a season-ending knee injury one week ago at Arizona, WSU struggled to find Motum help on offense as no other player reached double figures. Senior forward Abe Lodwick and junior guard Reggie Moore each had nine points.
Despite that, the Cougars appeared poised for a blowout win when junior guard Mike Ladd, who had been sidelined with a right thumb injury since Jan. 5 against Colorado, made a pair of free throws to extend their lead to 45-31 during the second half.
But WSU, which played man-to-man defense for the entire game, struggled to contain the Trojans' outside shooters. Guard Greg Allen scored a season-high 17 points on 5 of 11 shooting on 3-pointers. Forward Garrett Jackson also made 3 of 6 from beyond the arc en route to 15 points.
"I give the credit to USC," Bone said. "They made some big shots."
THE LATTER COMPLETED a three-point play after Jackson was fouled on a shot to cut the Cougars' lead to 58-53 with 1:39 left. But USC missed its final three shots before Motum converted a pair of free throws with 17 seconds remaining to secure the victory.
Bone said he mostly was happy with the Cougars' defense. It was the second consecutive game they played nearly exclusively a man-to-man scheme following the 71-67 loss at ASU. The Sun Devils shot 54.5 percent in that game.
"We challenged the guys the last few days about our man-to-man defense," Bone said. "We know what Arizona State did against us."
One significant difference was free throws. While the Sun Devils had 28 attempts from the stripe, the Trojans had just three.
"We were able to play aggressive and alert," Bone said. "We weren't just fouling."
WSU has won eight of its last nine games at Friel Court against USC, but has not defeated UCLA at home since 1993. The Cougars host the Bruins at 2 p.m. Saturday (TV: Root Sports).
"The home feeling just gets you into games," Motum said. "We need to protect this place."
"I just instinctively told Mike to get in there," Bone said. "I was really impressed with his defense."