Defense was expected to be the story for USC and Washington State in Saturday night’s Pac-12 matchup — after all, WSU has one of the better defensive units in the conference while USC is among the nation’s stingiest teams.

It wasn’t exactly a defensive masterpiece, but the Trojans did just enough to pick up a wire-to-wire 85-77 victory over the Cougars at the Galen Center. It’s USC’s ninth straight victory over its Pac-12 North foe and sixth straight overall, as the Trojans move to 5-1 in conference play.

USC was paced by redshirt senior guard Tahj Eaddy, who poured in a season-high 21 points on the night via an efficient 62% from the field.

His 14 first half points helped the Trojans take a 12-point lead into the break.

“I was disappointed he missed three free throws, because he’s an 83% shooter,” head coach Andy Enfield joked after the game. “He played outstanding basketball tonight … He just had a good rhythm tonight and really helped us on the offensive end.”

Freshman forward Evan Mobley was USC’s second-leading scorer with 16, right around his season average of 16.3 entering the night.

Despite Eaddy’s hot start, the Cougars several times came within double-digits in the second half, but the Trojans consistently answered back. With 14 minutes remaining and WSU down by nine, the Cougars had a chance to inch closer. But a steal and redshirt senior forward Chevez Goodwin transition bucket led to a technical foul on WSU head coach Kyle Smith. Junior guard Drew Peterson sank the two free throws to put USC up by 13.

Less than a minute later, with USC up 56-47, a Peterson steal and Max Agbonkpolo fast break dunk — which featured impressive breakaway speed by the sophomore forward — plus another WSU turnover and an Evan Mobley layup again brought the Trojans’ lead back to 13.

The Cougars cut it to eight points with 9:22 to go, but a Peterson second-chance putback preceded a WSU pass straight into the arms of Agbonkpolo, and Peterson followed with a 3-pointer.

The sequence was part of Peterson’s second-half surge that saw him put up 11 points in the final 20 minutes after scoring just four in the opening half. Peterson also grabbed 11 rebounds, including three on the offensive end, to lead the Trojans.

“I’m not only trying to score out there. I like to fill up a stat sheet in different aspects,” Peterson said. “I try to affect the game in any way I can. One of my main things these past few games has been really trying to rebound and help the Mobleys out down there, help [Goodwin] out down there.”

Again up by double digits, it seemed as though USC had put the nail in the coffin.

Wazzu had other plans.

The Cougars cut it to a mere four points on a 3-pointer by sophomore guard Noah Williams with just over three minutes left. But the Trojans followed with a 6-0 run, punctuated by an Isaiah White reverse layup after multiple offensive rebounds. The display of effort from the redshirt senior guard put the Trojans up 10 and the game out of reach with less than a minute to go.

“We scored 46 in the second half, they had 50, which is a lot — both teams … When they did make a couple of those tough shots, we were able to come down and put points up on the other end,” Enfield said. “If you can’t stop the other team, you’d better score with them.”

White finished the evening with 13 points on just six field goal attempts.

USC’s foul trouble was a key contributor to the Cougars’ late life, as Wazzu entered the bonus just 6:30 into the second half. The Mobley brothers were particular contributors: Evan finished with four fouls and Isaiah finished with three as both sat key minutes down the stretch, allowing WSU to keep things interesting.

The Cougars were led by senior guard Isaac Bonton’s 27 points on 10-of-21 from the field and 4-of-8 from behind the arc.

Still, Bonton didn’t receive enough help to overcome a Trojan lead that reached as high as 15 points thanks in large part to Eaddy — whose contributions kept USC’s offense afloat even without the typical impact of the Mobleys and as sophomore guard Ethan Anderson continues to return to full strength.

“Maybe in terms of shooting,” Eaddy said when asked if Saturday was his best game. “But I don’t really consider my best game just me scoring points. I consider it just affecting the game … Just trying to affect the game in every way.”

USC will travel to Corvallis, Oregon, to take on Oregon State Tuesday at 4 p.m.

“We got another three-game stretch this next week, and I think it’s just gonna take consistency,” Peterson said. “We got a consistent defense that sets the tone, and we just gotta bring the offensive end every night. Consistency is what is gonna get us this Pac-12 title, and we’re ready to go with it.”