TUCSON, Ariz. (AP) -- UCLA's coaches had planned all along to use Myles Jack on offense sometime. They got around to it Saturday night with spectacular results.
The freshman linebacker rushed for 120 yards on his first six carries of the season, including a 66-yard touchdown that helped the 16th-ranked Bruins beat Arizona 31-26 Saturday night.
''I thought they were jokin' about it the whole year,'' Jack said, ''but they finally just threw me back there and I just followed my blockers and everything worked out.''
On defense, Jack had eight tackles and recovered Ka'Deem Carey's fumble in the UCLA end zone as the Bruins won in Tucson for the first time since 2003.
And make no mistake about it, Jack considers himself a defensive player.
''I like to hit people,'' he said, ''rather than be hit. That's more my mentality, but whatever the team wants me to do, I'm with it.''
Brett Hundley passed for two touchdowns and ran for another as UCLA (7-2, 4-2 Pac-12) stayed a game behind first-place Arizona State in the Pac-12 South. Carey rushed for 149 yards on 28 carries for the Wildcats (6-3, 3-3), running his school-record string of consecutive 100-yard rushing games to 12.
Hundley threw a 66-yard touchdown pass to Shaq Evans on UCLA's first offensive play. Evans also had a 4-yard scoring catch.
Arizona's B.J. Denker had a pair of fourth-quarter touchdown passes to Nate Phillips.
The Bruins were without starting running back Jordon James, who aggravated a right ankle injury a week earlier against Colorado, and they turned to the 18-year-old Jack to fill in at crucial times.
UCLA coach Jim Mora Jr. said Jack's performance was ''remarkable, but it doesn't surprise me.''
''I've been fortunate to know this young man since he was about 12 years old,'' Mora said. ''I don't think that anything he's ever done or is going to do is going to surprise me. He's a tremendous kid from a great family. He cares about his team. He'll do anything to help us win.''
Arizona coach Rich Rodriguez called Jack ''a great athlete, a great player.''
''He'll be a first-round pick as a linebacker,'' Rodriguez said. ''We tried to recruit him as a running back. He's really good. We didn't tackle him.''
A pass interference penalty on third down kept Arizona's eight-play, 88-yard TD drive alive and Carey's runs of 22 and 24 yards set up Denker's 15-yard touchdown pass to Nate Phillips that cut UCLA's lead to 24-19 with 11:46 to play. The two-point conversion pass failed.
Then on third-and-1 from the UCLA 24, Jack burst through the line and down the right sideline 66 yards for a touchdown to make it 31-19 with 10:46 to go.
Arizona quickly responded, going 75 yards in 2:44, with Denker throwing 14 yards to Phillips to cut the Bruins' lead to 31-26 with 8:02 remaining.
The Wildcats got the ball twice more but couldn't move it. Ishmael Adams' interception of Denker's pass on fourth down from the Arizona 15 sealed it with 1:46 to play.
On UCLA's first play on offense, Hundley connected with the streaking Evans, who got behind Jonathon McKnight for 66 yards and a touchdown. The Bruins led 7-3 and never trailed again.
After the subsequent kickoff, the Wildcats drove deep into UCLA territory, but on fourth-and-a-foot from the 15, Carey was stopped for a 1-yard loss and the Bruins took over. Hundley had a 17-yard run and scrambled for a 15-yard touchdown to cap UCLA's 12-play, 84-yard scoring drive that made it 14-3 with 1:23 left in the first quarter.
The Bruins helped Arizona to its first touchdown when they tried a fake punt from their own 25. Sean Covington overthrew a wide-open Jack on the play, and the Wildcats scored four plays later - Carey on a 4-yard run that cut it to 14-10 with 12:55 left in the half.
It stayed that way until UCLA, behind the running of Jack, went 90 yards in 16 plays. McKnight deflected Hundley's pass in the end zone, but Evans was able to bring it down and drag his toes inbounds for the touchdown with 16 seconds left in the half and give the Bruins a 21-10 lead at the break.
UCLA added a 34-yard field goal by Ka'imi Fairbairn on its first possession of the second half, then Arizona drove from its 12 to first-and-goal at the Bruins 5. Carey took the ball up the middle and was slammed by the defense, sending him into a head-first flip. He lost the ball just before crossing the goal line, and Jack recovered in the end zone for a touchback that kept it a two-touchdown lead.
''I'm passionate when I run the ball,'' Carey said. ''I'm just trying to get in the end zone. I just closed my eyes and took a leap, anything to help my team. The defense knocked the ball out and made a good play.''
Arizona got a short field to work with again when UCLA's Damien Thigpen fumbled and Marquis Flowers recovered for the Wildcats at the Bruins 28. The Wildcats moved to the 4 but on third-and-1, Jordan Zumwalt slammed Denker to the ground for a 6-yard loss and Smith's 27-yard field goal made it 24-13.