TUCSON, Ariz. - UCLA true freshman quarterback Josh Rosen easily passed his first Pac-12 test, but he had lots of help.

Rosen often had all the time he needed in the pocket, and the Bruins rolled to 213 rushing yards as No. 9 UCLA posted 42 first-half points in an early Pac-12 showdown before coasting to a 56-30 victory over 16th-ranked Arizona on Saturday night.

Rosen, in the national spotlight with ESPN's College Football GameDay on campus for a prime-time game, completed 19 of 28 passes for 284 yards with two touchdowns and no interceptions.

"Once again we relied on the strength of our team, which is the offensive line," said UCLA coach Jim Mora.

Running back Paul Perkins scored three touchdowns and receiver Jordan Payton had 136 yards on seven catches for UCLA (4-0, 1-0 Pac-12), which took advantage of three first-half turnovers from Arizona. The Wildcats (3-1, 0-1) lost quarterback Anu Solomon to a head injury in the second quarter and coach Rich Rodriguez did not have an update on his status after the game.

Rosen had 212 passing yards in the decisive first half.

"We didn't get any pressure, which is disappointing. We didn't get any pressure at all on him," Rodriguez said. "We allowed him to get comfortable. And when you allow a good thrower to get comfortable, they are going to make some plays."

Arizona scored the first nine points of the second half to cut UCLA's lead to 42-23, but the Bruins answered with a 75-yard touchdown drive, capped by Rosen's 8-yard run. That made it 49-23 with 3:39 to go in the third quarter.

Mora improved to 4-0 against Rodriguez. The Bruins are 15-4 on the road under Mora.

UCLA entered the game as the highest-ranked Pac-12 team and further stamped itself as the team to beat and a College Football Playoff contender, although Mora was unhappy with a defense that gave up 468 yards and a pair of 100-yard rushers.

The Bruins were playing their first game without All-American linebacker Myles Jack, who suffered a season-ending knee injury in practice last week.

Mora said he was "sick" about the rush defense.

"Nothing impressed me about the defense," he said. "It's unacceptable and it won't happen again."

Arizona backup quarterback Jerrard Randall, known for his athleticism and not his passing, rushed for 128 yards and a touchdown on 16 carries. But he completed only 4 of 16 passes for 45 yards with a touchdown and one interception.

Solomon was 4 of 10 for 55 yards, with two lost fumbles, before he left the game. Arizona running back Nick Wilson rushed for 136 yards, his third consecutive game in triple digits. The Wildcats got back All-American linebacker Scooby Wright, who had been out since the first quarter of the opener because of a knee injury. He finished with seven tackles.

UCLA took advantage of three first-half Arizona turnovers - scoring touchdowns after each - although the Bruins offense didn't need the help. UCLA rolled to 329 yards in the first half and scored on six of its seven first-half drives in taking a commanding 42-14 halftime lead.

"There were some unforced errors certainly," Rodriguez said. "You have to give them some credit with how they played, but as I told our guys, maybe you want something so much, you press a little it. Seems at times we were pressing a little too much instead of just playing."

The teams exchanged touchdowns on their opening possessions before UCLA got the first big break, recovering a fumble at the Arizona 16 after a high shotgun snap sailed past Solomon. Perkins swept outside on the next play for a 16-yard score and a 14-7 lead.

The Bruins took advantage of a second Solomon fumble at the Wildcats 30 to push the lead to 28-7. Rosen connected on a 5-yard pass to Payton.

Solomon left the game with 10:56 to go in the second quarter after taking an inadvertent blow to the head at the end of a run. Randall came in and sprinted 39 yards for a touchdown on his first play to make it 28-14. He previously had scoring runs of 57, 72 and 73 yards on only six carries in the first three games.

UCLA countered with another touchdown and then an interception of Randall by cornerback Ishmael Adams. Perkins finished the ensuing drive with his third touchdown of the half, a 1-yarder with 3:08 before the break.

NOTES: UCLA CB Ishmael Adams made his season debut after coach Jim Mora lifted his suspension early this week. That came after it was announced Adams would not face felony robbery charges for allegedly taking a cell phone from an Uber driver. ... ESPN's College GameDay program made its second appearance in Tucson on Saturday morning. It previously was in town in November 2009 for Arizona's game against Oregon. ... Arizona WRs Trey Griffey and Tyrell Johnson have missed the first four games of the season because of foot injuries. ... The Bruins have lost three starting defensive players for the season because of injury - LB Myles Jack, DT Eddie Vanderdoes and CB Fabian Moreau.