Quarterback Josh Rosen passed for 350 yards and accounted for four touchdowns, UCLA scored on every possession after halftime and the Bruins handled injury-riddled Arizona 45-24 on Saturday night in Pasadena, Calif.

Rosen threw three touchdown passes and scored on a 1-yard keeper early in the fourth quarter for a 31-10 lead. Rosen and the offense wasn't sharp early, but UCLA (3-2, 1-1 Pac-12) put up 31 points after halftime, scoring on its five full second-half drives.

Rosen completed 20 of 37 passes, including a 62-yard touchdown throw to receiver Kenneth Walker III on the final play of the first quarter.

UCLA wide receiver Darren Andrews caught nine passes for 108 yards and scored on a 26-yard run with 3:30 left.

Arizona (2-3, 0-2) was without season-opening starting quarterback Anu Solomon (knee) for the fourth game, and his replacement, Brandon Dawkins, left in the first half with a rib injury. Coach Rich Rodriguez tried walk-on Zach Werlinger for a few series before burning the redshirt of true freshman dual-threat Khalil Tate midway through the third quarter.

Tate had some punishing runs, carrying 15 times for 79 yards, and he completed 5 of 9 passes for 72 yards and two scores. He had a 31-yard scoring pass to receiver Shun Brown and a 13-yarder to receiver Cam Denson in the final minute.

The Wildcats also lost running back Nick Wilson, who played briefly after missing almost all of two games with an ankle injury. Converted slot receiver Tyrell Johnson took over the decimated position, rushing 16 times for 77 yards.

UCLA special teams contributed a 33-yard punt return and two kick returns of 50-plus yards, setting up the offense in Arizona territory each time.

Walker ended up with four catches for 114 yards. Running back Nate Starks led UCLA's running game with 17 carries for 80 yards.

UCLA coach Jim Mora improved to 5-0 against Arizona.