UCLA’s Wilton Speight went 17 for 27 for 204 yards and two touchdowns after relieving the injured Dorian Thompson-Robinson in the second quarter.
Rhett Rodriguez, making his first career start in place of the injured Khalil Tate, went 15 for 34 for 231 yards with two TDs and two interceptions.
Arizona trailed 17-7 at halftime, but rallied by scoring 13 unanswered points to grab a 20-17 lead late in third quarter.
UCLA scored easily on its next two drives, which bookended a UA TD drive, allowing the Bruins to re-take a 31-27 advantage with 11:33 left in the fourth.
Josh Pollack chipped a 29-yard field goal to cut UCLA’s lead to 31-30 with 6:28 left, but the Bruins picked up three first downs on their ensuing drive to milk the clock and hold on for the win.
Arizona falls to 3-5 overall and 2-3 in the Pac-12, greatly lessening its chances of reaching a bowl game.
The Wildcats outgained the Bruins 520-460, but lost the turnover battle, committing three to UCLA’s one. Two of those giveaways were extremely costly.
Trailing 10-0 in the second quarter, J.J. Taylor broke free for 55 yards, but was stripped as he neared the goal line and UCLA recovered for a touchback.
Earlier, an Arizona drive ended when a floating pass by Rodriguez was intercepted in the end zone.
Still, it was a solid night for Taylor, who carried the ball 19 times for 154 yards and a touchdown. Gary Brightwell chipped in with 121 yards on 15 carries, including a 72-yard scamper that set up a Pollack field goal.
Arizona’s defense had its moments — it had 12 tackles for loss including a Dereck Boles strip-sack that set up the offense in the red zone — but continued to struggle on third down, allowing UCLA to go 8 for 18.
The Bruins shot themselves in the foot all night long, committing 12 penalties for 103 yards.
Thompson-Robinson was 5 for 8 for 103 yards and a TD before leaving with an injury after taking a sack from Colin Schooler.
Rodriguez, who was inconsistent but made some gritty throws, tossed a 17-yard TD to Shawn Poindexter to cut UCLA’s lead to 10-7 midway through the second, and connected again for an 11-yard TD to tie the game at 17 with 8:54 left in the third.
Pollack then drilled a 39-yard field goal to give Arizona its first lead with 4:58 left in the third and Taylor plunged for a one-yard touchdown to put UA ahead 27-24 with 12:34 to go in the fourth.
But UCLA always had an answer. Joshua Kelley, who rushed for 136 yards, broke free for a 28-yard TD, giving the Bruins just enough offense to capture their second win of the season.
The Wildcats were without starting cornerbacks Tim Hough and Lorenzo Burns. Coach Kevin Sumlin announced after the game that Hough is no longer with the team.
UCLA’s 307 passing yards were the second-most Arizona has allowed all season.