TUCSON, Ariz. -- Oregon appeared to be well on its way to victory, on the cusp of clinching a share of the Pac-12 title behind its always-potent offense.
The sixth-ranked Ducks wanted to finish with a flourish and did just that with their defense, never giving Arizona a chance.
Sabrina Ionescu scored 22 points and No. 6 Oregon held Arizona scoreless in the fourth quarter to clinch at least a share of its second straight Pac-12 title with an 83-54 victory Friday night.
"That was a surprise until I looked at the box score; I thought it was in the wrong column," Oregon coach Kelly Graves said. "But that's the kind of competitors we have."
The Ducks (26-3, 15-2) wrapped up the No. 1 seed in the conference tournament. They blew out Arizona in the first meeting, but had to build their lead gradually after an early push by the Wildcats.
Oregon led by eight at halftime and stretched the lead to 17 before outscoring Arizona 19-0 in the fourth.
The Ducks shot 64 percent and had a 50-16 advantage in the paint to put themselves in position to win the conference title outright Sunday against No. 21 Arizona State.
Ionescu also had eight assists and five rebounds. Satou Sabally added 16 points and 10 rebounds.
"We don't want to share," Kelly said. "We want to win it outright. I think we can do it. That's how this team is driven."
Arizona (17-11, 7-10) was much better early than the first game, but had a hard time stopping Oregon or getting shots to fall in the fourth quarter to lose its sixth straight to the Ducks.
Aari McDonald led the Wildcats with 26 points.
"The difference between good teams and top-10 teams is they're always ready, you can never relax," Arizona coach Adia Barnes said. "They make you pay."
A year ago at McKale Center, Oregon closed out its first Pac-12 championship in 18 years with a 74-61 victory that left Graves choked up.
The Ducks returned to the desert with a chance to clinch at least a share of a second straight title against a team they dominated the first go-round.
Oregon scored the first 20 points and was up 31-4 after the first quarter in the teams' first meeting on Jan. 20, rolling to a 93-60 victory in Eugene.
Arizona got off to a much better start in the rematch, eclipsing its earlier first-quarter total in the first 2:15 and kept Oregon within reach after one quarter.
The Wildcats had a hard time slowing the nation's third-best shooting team, but were still within 20-16 after Ionescu hit a long 3 at the buzzer.
Oregon kept hitting shots -- 17 for 31 -- and used a 9-0 run to lead 40-32 at halftime. Ionescu had 16 points by halftime and McDonald 15 for Arizona despite hitting her face on the floor after blocking a shot.
The Ducks continued to fly in the third quarter, using a 9-0 run to push the lead to 17 midway through.
Arizona got no closer than 10 the rest of the way.
"We really stayed with them from the majority of the game," said Arizona senior Lindsey Malecha. "They're a top-10 team and that shows we can stay with them."
Oregon bounced back from consecutive losses with two outstanding offensive performances against USC and Arizona.
Arizona got off to a much better start against the Ducks, but still couldn't match their offensive firepower nor get a shot to fall in the fourth quarter.
Oregon: At No. 21 Arizona State on Sunday.
Arizona: Hosts No. 9 Oregon State on Sunday.
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