LAS VEGAS (AP) Arizona opened with a big run, UCLA fought back and went on a run of its own. The Bruins had the next run, and the Wildcats went on a bigger one, only to have UCLA claw back again.
The Pac-12's two stories programs, one epic game. And it was only the semifinals.
Brandon Ashley scored a career-high 24 points and No. 5 Arizona withstood a late rally to beat UCLA 70-64 on Friday night to earn a return trip to the Pac-12 Tournament championship game.
''We knew we were going to play in a game like we were going to play tonight,'' Arizona coach Sean Miller said.
Arizona (30-3) started strong, then sputtered against UCLA's zone for long stretches before putting together a 15-0 run in the second half as the huge contingent of Arizona fans made the MGM Grand Arena feel like a home game for the Wildcats.
UCLA (20-13) rallied, pulling within 66-64 behind a 3-pointer by Norman Powell and another by Kevon Looney with 19 seconds left, but Arizona closed it out from there.
T.J. McConnell hit two free throws, Rondae Hollis-Jefferson blocked Looney and Ashley hit two more free throws to seal it.
Now the Wildcats are headed into Saturday's championship game against Oregon or No. 17 Utah after being knocked out by UCLA the past two seasons.
''You could say last year we didn't get over that hump, but today we did,'' said McConnell, who had 10 points and 11 assists.
UCLA struggled with foul trouble and never made it all the way back after Arizona's big run.
Isaac Hamilton, who scored 36 points in the quarterfinals, fouled out and was limited to six points in 15 minutes. Parker scored 15, but also had foul issues.
Powell finished with 21 points and Tony Parker added 15 for the Bruins, who now must wait for Selection Sunday to see if they'll get into the NCAA Tournament.
''I like our chances,'' UCLA coach Steve Alford said. ''We're like a lot of people going to sit and wait. I've been doing this a long time watching throughout the country that there's 31 better at-large teams than what we are.''
UCLA ended Arizona's bid to win the regular-season and tournament titles a year ago, beating the Wildcats in the championship game.
Arizona raced past California in the quarterfinals after a slow-starting first half and UCLA blew past rival Southern California into the semifinals.
The Wildcats won the teams' lone meeting 57-47 on Feb. 21 in a gritty game. Arizona's starters struggled - outscored 24-0 in runs to open each half - and the Wildcats got an unexpected lifts from Dusan Ristic and Gabe York, who combined for 25 points.
Arizona had no trouble getting going in the semifinals, jumping out to an 11-2 lead in the opening four minutes.
Then it was back to struggling against UCLA's zone and finishing at the rim, with usually-efficient McConnell turning it over four times.
Arizona turned it back for a little while, going on a small run after Hamilton and Parker each went to the bench with three fouls. UCLA fought back and tied it at 27 after Alford turned a steal into a buzzer-beating 3-pointer.
The Bruins fed off the last-second shot, making seven of their first 10 shots to build a 47-40 lead.
But then, with a flick of a switch, Arizona turned McKale Center West into a mosh pit, ear-ringing roars coming with each made shot during the 15-0 run that put the Wildcats up 55-47.
''We were down 47-40, and we all just said we have to dig deep for this one, whatever heart you have, you have to give more,'' McConnell said. ''And we went on a run, and our fans were behind us.''
Powell shot the Bruins back into it, hitting a big 3-pointer from the corner and finding Parker under the basket with 1:02 left. UCLA hit a couple more big shots, but never was able to finish it off.
''I'm proud of the way not only myself, but the team fought and kept battling through the adversity that hit us,'' Powell said.
UCLA: Looney played while wearing a clear mask after suffering a facial injury against USC. He had five points.
Arizona: Ashley was 5 for 6 from the floor for 12 points in the first half, while his teammates went a combined 4 of 19. ... Rondae Hollis-Jefferson had 12 rebounds.
UCLA: must wait until Sunday to see if it will get an NCAA Tournament invite.
Arizona: faces the winner between Oregon and No. 17 Utah in Saturday's championship game.