With Arizona trailing 77-76 with 2:53 left, Trier, standing at the 3-point line, floated a pass to Deandre Ayton who soared, caught it one-handed, and flushed it to put UA ahead.
On the next possession, Trier hit a contested 3 to push Arizona’s lead to 81-77 before making two free throws to give the Wildcats a six-point advantage with 1:39 left.
The Ducks, who had erased multiple double-digit deficits in the game, had no answer this time.
The Wildcats improve to 14-4 and 4-1 in the Pac-12, tied with UCLA atop the conference standings. It’s their second win in a row after knocking off Oregon State on Thursday.
“It was a huge win, especially because Oregon is rolling right now,” said UA guard Rawle Alkins. “They had a big win out in Phoenix when they beat ASU. We didn’t want to lose because we have to protect our home court, and especially because last time they came out here, they beat us.”
Trier was 6-14 from the field (2-8 from 3) and made all 11 free-throw attempts. Ayton added 24 points and seven rebounds. The big man was 7-11 from the field and 10-11 from the line.
Alkins (13) and Parker Jackson-Cartwright (10) each scored in double figures and had six assists.
Keanu Pinder played 18 minutes, the second-most he’s played all year, giving Arizona a boost on defense and a season-high six points, including this vicious dunk:
Keanu Pinder just stole a man's soul! pic.twitter.com/1WgOLlXDMl— Christopher Boan (@cgboan) January 13, 2018
“We wouldn’t have won this game if it wasn’t for Keanu,” Alkins said.
Oregon was led by Elijah Brown and MiKyle McIntosh who posted 25 and 20 points, respectively.
Arizona led by 11 with 16:43 left in the second half, but those two helped the Ducks rally to tie it at 55 just four minutes later.
And later a 3 by McIntosh put the Ducks ahead 58-57 midway through the second half. Arizona quickly re-took the lead, but Brown sank a corner 3 to put Oregon up 69-68 with seven minutes left.
Brown was 6-9 from 3 as Arizona struggled to track him around the perimeter.
The New Mexico transfer was later fouled by Alkins behind the arc, and he made all three free throws to extend UO’s lead to 75-71 with 5:40 to play.
Alkins made up for it with a timely 3 of his own, then two free throws by Ayton gave UA a 76-75 advantage with 4:33 left.
The Ducks would the lead back briefly before Trier’s clutch moments and some stingy UA defense, which closed out a two-hour, 20-minute game.
“Our defense won the game,” Alkins said.
Arizona and Oregon shot 54 percent and 47 percent, respectively, but the flow of the game was choppy thanks to 51 fouls and 32 turnovers.
Arizona took 37 free throws and made 34. Oregon went 21-24 from the stripe.
“That overcame the 17 turnovers,” Arizona coach Sean Miller said of his team’s free-throw shooting. “And then rebounding we did a good job against them. I know they had nine second shots, but I think overall we were pleased with a lot of other things other than our turnovers.”
The Wildcats outrebounded the Ducks 27-23, but Oregon had a 12-4 edge in second-chance points.
The Ducks were 8-27 (30%) from 3, while Arizona was 6-15.
Arizona led 41-38 at halftime which was a disappointing result for the Wildcats, all things considered.
They led 32-19 with 6:26 left, but the Ducks rattled off a 12-0 run to make it a 32-31 game with 3:52 left.
Arizona missed all five of its shots and had four turnovers during that stretch, ruining what had been an outstanding first half offensively. There were also a lot of whistles which slopped up the game.
Still, the Wildcats shot 50 percent in the period, despite missing nine of their last 10 field goal attempts.
“We had bad pockets,” Miller said. “We had two four-minute segments in the game that we might have had eight or nine total turnovers in that period of time.
“We were consistent other than those pockets, but when you get down late in the game at home and things aren’t going your way, sometimes you just look at each other and say ‘not today.’ The opposite happened for us. Our free-throw shooting is one of our team’s greatest strengths ... and it is the biggest reason we won.”
Arizona extended its lead to 41-36 after two free throws by Ayton before Roman Sorkin scored with 14 seconds left for the period’s final bucket.
Dusan Ristic and Ayton each had 10 points in the first half. Trier had nine.
Ristic, who only played 15 minutes because of foul trouble, did not score in the second half.
There were several questionable calls on both sides, and Miller had to be restrained at halftime after a deflected ball clearly off Oregon was awarded to the Ducks.
Brown was assessed a technical foul in the first half for his reaction after being fouled by Brandon Randolph.
The UA freshman went for a chase-down block, but slapped Brown on the wrist. Brown had words with Randolph which the refs evidently didn’t appreciate.
Brown made both his free throws and Trier made the technical free throws to make it a 32-21 game with 6:26 left.
Arizona’s inside-out ball movement was crisp early on, sinking six of its first seven shots, including three 3s, against Oregon’s matchup zone.
But Arizona missed its next eight 3s and Oregon scored 14 points off Arizona’s 11 first-half turnovers allowing it to get back in the game.
Arizona outscored Oregon 49-45 in the second half.
“I believe that today, for a lot of reasons, was our best overall win of the season,” Miller said. “One of those reasons is the respect we have for Oregon. ... Dana (Altman) is one of the great coaches in our game and it is hard to play against those guys. They do it on defense. They do it on offense. They have guys that off the bench that really contribute, and it’s always a hard fight.
“I think that’s why it’s so thrilling to beat them. You have to earn it and tonight we did.”
The Wildcats head to the Bay Area next week to take on Cal and Stanford on Wednesday and Saturday, respectively.
Follow Ryan Kelapire on Twitter at @RKelapire