LAS VEGAS -- Oregon could only watch after squandering a 17-point second-half lead and fouling a shooter with no time left in regulation.

Arizona forward Mark Tollefsen missed the first free-throw attempt but made the second to tie the game at 77.

"Fortunately, he missed one for us," said Ducks guard Tyler Dorsey, who finished with 19 points. "We knew we had to throw that away in regulation and get ready, regroup in overtime, and that's what we did. "We came out and jumped on them right from the beginning."

Forward Elgin Cook scored 22 points, Oregon hit two big 3-pointers in overtime and the eighth-ranked Ducks did indeed survive, beating No. 15 Arizona 95-89 Friday in a Pac-12 Tournament semifinal Friday.

Arizona trailed 77-73 in regulation when Oregon forward Chris Boucher missed two free throws with 12.8 seconds left. Arizona guard Gabe York then sank a 3-pointer with 0.7 seconds left.

Tollefsen stepped in front of Oregon forward Dillon Brooks along the baseline to steal the inbounds pass and he was fouled by Brooks on a one-handed shot attempt with no time left on the clock.

"As a basketball player, as a young player, you dream of those moments," said Tollefsen, who also nailed a 3-pointer with 17.8 seconds left.

"I was glad I at least made one. Would I have liked to make both? Of course. But to give our team another opportunity to beat these guys was good. ... As tough as it is to lose, I did enjoy the moment."

Oregon (27-6) advances to play Saturday night against second-seeded Utah in the other semifinal at the MGM Grand Garden Arena. The Ducks are looking for their first conference tournament title since 2013.

Arizona (25-8) awaits its seed and destination for the NCAA Tournament on Sunday.

In overtime, Oregon guard Dwayne Benjamin, fresh off the bench after sitting the final 8:32 of regulation after he limped off the court, hit a 3-pointer, followed by another trey by Brooks, who scored 19 points.

"I didn't plan on putting him back in," Oregon coach Dana Altman said of Benjamin, "but he said he was good to go. Tyler lose his shoe and I just thought it would give Tyler a one-minute blow, and he hit a big shot."

York hit a trio of late 3-pointers in overtime but it wasn't enough as Oregon made 9 of 12 free throw attempts in the final 1:25 to hold off the Wildcats.

That was a contrast to the second half, in which the Ducks made 6 of 16 from the foul line.

"Let's go something that we normally shoot, and that game is over," Altman said.

Oregon was up 44-29 at halftime, pushed it to 17 and was up 10 with 5:20 to play before Arizona rallied to tie with four points in the final second.

York had 21 points to lead Arizona. Guard Allonzo Trier had 16 points but fouled out with 2:35 in regulation. Center Kaleb Tarczewski has 11 points and 12 rebounds.

Arizona hasn't lost by double-digits in more than three years, since an 89-78 defeat at USC on Feb 27, 2013, which was 118 games ago.

Oregon's length and athleticism on the perimeter was difficult for Arizona to handle. Oregon, which blocked eight shots and had six steals before half, finished on a 15-2 run, including a buzzer-beating dunk by Brooks

"There is no easy solution with matchups," Arizona coach Sean Miller said of Oregon's offense.

"I respect their team a great deal. To me why they are so good is because of how together they are. And that's the ultimate compliment in basketball because that group of five has to play offense and defense.

"They're not the biggest group, but I'll tell you this, there is not a hard-working more-together team than them."

NOTES: Oregon F Chris Boucher on Thursday became the first player in Pac-12 history and the first at the NCAA Division I level to have 100 blocks and 30 3-pointers in the same season. ... Oregon PG Casey Benson entered the game as the nation's leader in assist-to-turnover ratio (4.3). ... Arizona PF Ryan Anderson had his 17th double-double of the season Thursday, the most at UA since C Jordan Hill had 20 in 2008-09. ... Arizona senior C Kaleb Tarczewski played in his 134th game at Arizona, moving into sole possession of fifth place on the school list.