TUCSON, Ariz. -- Just because guard Allonzo Trier is back doesn't mean everything is right with the Arizona Wildcats.

Trier scored a team-high 17 points in his season home debut and forward Lauri Markkanen had a double-double Thursday night, but No. 7 Arizona couldn't pull away from Washington State until late in a 79-62 Pac-12 victory Thursday night.

"It's going to make the team feel funny," Trier said of his return to the court. "We're still a ways away from our ceiling."

Trier, a sophomore who returned Saturday at UCLA after missing the first 19 games because of an NCAA suspension, added a career-high seven assists. He tested positive for a performance-enhancing drug and although the school won an appeal, Trier had to sit until the banned substance was out of his system.

Trier practiced with the team during his suspension, but it's still an adjustment during games.

"For us, having Allonzo back is a gift," coach Sean Miller said.

"And this has nothing to do with Allonzo or our team, but the reality of adding a player after 19 games of him not playing is that there are things we have to get better at and work through. It's going to take us a few weeks."

Markkanen, a 7-foot freshman, drained 4 of 7 from 3-point range and scored 16 points to go with 13 rebounds. It was his third double-double of the season. He made 52 of 103 3-point shots this season, with his 50.5 percentage ranking second behind Steve Kerr (57.1) on the school's career list for accuracy.

"For him not to be considered one of the best freshmen in college basketball is a complete joke," Miller said.

Arizona (19-2, 8-0 Pac-12) won its 13th consecutive game and ended with a 23-9 run when its superior depth and talent took over. The Cougars (10-10, 3-5) lost five of their past six games.

"I'm proud of these guys for hanging in here," Washington State coach Ernie Kent said. "The physical part we were great at for 30 minutes. The mental part got away from us in the last six minutes and so did the physical part, because we got fatigued and they took advantage of that."

Washington State center Conor Clifford scored a team-high 19 points. Guard Malachi Flynn had 12 points.

"Our team has great talent," Clifford said. "When everyone is sharing the ball and we get it moving around, find each other, we get into a rhythm. Then we start scoring really well."

Washington State scored the first six points of the second half to tie the score at 39. Arizona regained the lead when guard Rawle Alkins stole a perimeter pass and went in for a fast-break layup.

The Wildcats never trailed after that but still had trouble pulling away, leading 56-53 with less than eight minutes to play. They got needed breathing room with a 9-0 run, capped by Alkins' 3-pointer.

Alkins scored 12 points. Arizona center Dusan Ristic had 13 points and seven rebounds.

Arizona led by 10 three times in the first half, but Washington State hit seven of its final eight shots of the half, including a 3-pointer by guard Ike Iroegbu with 1:29 left to pull the Cougars within 34-31. Arizona answered with a Markkanen 3-pointer and led 39-33 at the break.

"It's a long regular season," Miller said. "It's not going to be perfect."

NOTES: Arizona won 11 consecutive games against Washington State, dating to the 2009-10 season, coach Sean Miller's first with the Wildcats. ... The Cougars haven't defeated a ranked team since 2007, when they beat No. 7 Arizona in Pullman, Wash. ... Former Arizona PG Nic Wise, who was a senior on Miller's first team, was in attendance. ... This was athletic director Greg Byrne's final event at Arizona. He accepted the same position at Alabama. ... Arizona hosts Washington on Sunday, when Washington State visits Arizona State.