LAS VEGAS -- Deandre Ayton was admittedly nervous in his first Pac-12 tournament game, awed by the size of the arena and the spotlight.
More comfortable and familiar with his surroundings, the Bahamian big man dominated his second go-round, sending the Wildcats into the title game for the second straight season.
Ayton scored seven of his 32 points in overtime and grabbed 14 rebounds, lifting No. 15 Arizona to a 78-67 victory over UCLA in the Pac-12 Tournament semifinals on Friday night.
"I had some butterflies the first game," Ayton said. "The nervousness went away and it was just business after that."
Ayton triggered a second-half resurgence after Arizona (26-7) labored offensively in the first half.
UCLA (21-11) matched Arizona nearly shot for shot, tying the game at 67 on Jaylen Hands' drive with 8 seconds left. His teammate, Aaron Holiday, missed on a runner at the buzzer after an Arizona turnover.
Then Ayton took over. He scored 13 straight points at the end of regulation into overtime and made 13 of 16 shots overall. He had 10 points on 4-of-14 shooting in the quarterfinals against Colorado.
Behind Ayton's massive performance and a defensive shutdown of UCLA in overtime, the Wildcats earned a chance to defend their Pac-12 tournament title against the Oregon-Southern California winner on Saturday.
"It gives our guys and our team a lot of confidence because if you can defend UCLA, I think you have an opportunity to defend some of the best offensive teams in this country," Arizona coach Sean Miller said.
UCLA answered every Arizona punch until overtime. The Bruins were no match for Ayton on defense and missed all seven of their shots -- six 3-pointers -- to go scoreless in overtime.
Thomas Welsh led UCLA with 17 points and 17 rebounds.
"We were probably a little bit run down, but at the same token, they had three guys play 40-plus minutes as well," UCLA coach Steve Alford said. "So that's not an excuse. I thought they stepped things up in the overtime and we were able to match that."
UCLA has boosted its NCAA Tournament hopes by winning eight of its last 11 games, including an 88-77 victory over Stanford in the Pac-12 quarterfinals. Holiday was superb in the win over the Cardinal with 34 points, eight assists and seven rebounds.
The Bruins won the lone regular-season meeting against Arizona, handing the Wildcats their only home loss by shooting 52 percent in an 82-74 victory on Feb. 8.
UCLA shot well at the start of the semifinal and so did Arizona. Then neither team could get much to fall.
The Bruins shot 4 of 16 from the 3-point arc and led 30-26 at halftime. The Wildcats were 3 for 13 from 3 and were nearly outrebounded by Welsh, who had 11 to their 13.
Arizona came out of halftime a different team, hitting seven of its first nine shots while building a 44-38 lead in the opening five minutes.
Ayton was the trigger point , hitting Parker Jackson-Cartwright for a pair of corner 3s on kickouts and making his first five shots.
But for all the Wildcats did right offensively, the Bruins matched them nearly shot for shot. UCLA kept the Wildcats within reach and Kris Wilkes pulled the Bruins even at 60-all with a vicious dunk with just under 5 minutes left.
UCLA had no answer for Ayton and will have a somewhat anxious wait on Selection Sunday.
Arizona woke from an offensive slumber in the second half and rode the coattails of Ayton into the title game.
UCLA's Aaron Holiday, the Pac-12's leading scorer, had 15 points but sure had to work for it. Arizona crowded him along the perimeter and swarmed him on drives, holding Holiday to 5 of 20 shooting and 3 of 12 from 3-point range.
"I saw another guy either in the paint or in the gap every time I drove," said Holiday, who had 34 points against Stanford. "So they did a great job on defense getting the ball out of my hands."
UCLA has to wait until Sunday to see if its resume is good enough to make the NCAA Tournament.
Arizona tries to repeat as Pac-12 tournament champions Saturday night.
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