UCLA did not come here to just give it a good try.

Their best defender back home, their top big man watching in a sweatsuit, the Bruins did not back down Saturday night at T-Mobile Arena while severely undermanned in a heavyweight title fight.

That much became clear during one stunning sequence late in the first half of the Pac-12 tournament championship.

UCLA’s Jaime Jaquez Jr. passed to a cutting Amari Bailey, who threw down a vicious, one-handed dunk over Arizona’s Pelle Larsson. The whistle blew. Bruins fans roared, presuming it was a chance for a three-point play.

Nope. The official motioned with his arm to signal that Bailey had pushed off. Offensive foul. UCLA coach Mick Cronin and the Bruins fans were livid.

It somehow got worse. On the Wildcats’ next possession, Larsson threw down his own one-handed dunk, prompting an Arizona fan sitting courtside to yell, “That’s how you do it!”

Bruised but not broken, the second-ranked Bruins kept landing counterpunches. But with the game up for grabs in the final minute, the No. 8 Wildcats delivered the knockout. Courtney Ramey hit a go-ahead three-pointer with 18 seconds left, after Tyger Campbell missed a potential tying free throw, Arizona added another at the line. Dylan Andrews missed a last-second three, sealing a 61-59 loss.

The Bruins battled all night, taking a nine-point lead early in the second half before it looked like they might run out of magic and their 12-game winning streak might end. Shots stopped falling. Fouls piled up.

With freshman center Adem Bona watching in a sweatsuit after injuring his left shoulder Friday, the Bruins ran out of big men in the final minutes when backup Mac Etienne fouled out with 9:35 left and Kenneth Nwuba followed with four minutes to go. Momentum was squarely in the Wildcats’ favor as they surged into a 50-48 lead on a Larsson three-pointer with nine minutes left.

UCLA rolled off six straight points to go back ahead by four and it seemed that the teams were headed for a taut finish.

Bailey’s pull-up jumper in the lane gave the Bruins a 58-56 lead with 2:42 remaining. Bailey had 19 points, the freshman guard heavily propping up his team’s offense, which went dry after that.

This was a chance to solve the debates, answer the questions, end any lingering doubts.

These two teams had met twice before this season, each winning once. The respective fan bases had made their cases for superiority. UCLA was the tougher, more complete team. Arizona possessed the bigger front line and a mightier offense.

The Bruins had won the Pac-12 title in a four-game runaway, thumping the Wildcats just last week, and now the teams were meeting again.

Would UCLA double down on success or go bust against its biggest nemesis?

Any reasonable calculus of the Bruins had changed considerably over the last week. Images of the Bruins running over to celebrate with their fellow students inside Pauley Pavilion were replaced by ones of UCLA fans crossing their fingers and holding their breath over the two asterisks that hovered like a dark cloud over the latest Arizona showdown.

Junior guard Jaylen Clark was out with a lower-leg injury. Bona, a shot-blocking menace, was transformed into a cheerleader by the shoulder soreness that’s not expected to keep him out past Saturday.

Even Nate Girma, the team’s athletic performance coach, wore a patch over one eye, symbolizing all the pain UCLA had absorbed.

The Bruins withstood it all as part of a stirring Pac-12 tournament run last week that was the stuff of Disney, pulling away from Colorado before blitzing Oregon behind a blitz of Campbell buckets.

But this challenge was on another level entirely, like going from scaling the Santa Monica Mountains to Mount Everest.

Bona’s expected return this week could keep the NCAA tournament selection committee from dropping the Bruins by a seed line or shipping them out of the coveted West Region.

The burning hatred between the teams was stoked again last week. Kerr Kriisa, the Wildcats’ headband-wearing, tongue-wagging point guard whom every Bruins fan loves to hate, retweeted a blurb about Jaquez winning Pac-12 player of the year alongside a crying emoji and an image of Wildcats star big man Azuolas Tubelis, Kriisa’s presumed pick.

Jaquez said winning player of the year wasn’t one of his three goals, which included winning the Pac-12 regular-season and conference titles in addition to a national championship.

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