UCLA hits, doesn’t bust in 37-3 victory over UNLV

Before UCLA quarterback Josh Rosen left Sam Boyd Stadium early Sunday morning, he turned philosophical.

“Live today, I’m about to learn tomorrow,” Rosen said.

Live and learn framed the 13th-ranked Bruins’ 37-3 victory over UNLV.

The Bruins learned their victory over Virginia in the season opener was more impressive than at first glance. The Cavaliers gave it more meaning when they rattled ninth-ranked Notre Dame, which pulled out a last-minute win, on Saturday.

The Bruins lived through a so-so performance by Rosen, the freshman who had become a national talking point after throwing for 351 yards and three touchdowns against Virginia.

UCLA (2-0) lived off running back Paul Perkins, who ran for 151 yards and two touchdowns.

UCLA learned that its defense can buy the offense time to find traction, as it did by dominating the Rebels (0-2).

It all started with Rosen.

“We just misfired in a few places here and there,” Rosen said. “A lot of it was on me. I don’t feel too proud how I played.”

Rosen picked up where he left off against Virginia, at the start anyway. He tossed a 29-yard touchdown pass to Jordan Payton for a 7-0 lead less than three minutes into the game. The rest of the game was a reminder that at this time last year he was playing for St. John Bosco High in Bellflower.

“We were just off just a tad,” Coach Jim Mora said. “That’s to be expected when you’re breaking in a new quarterback.”

Rosen completed 22 of 42 passes for 223 yards. He had one pass intercepted.

There was a difference of opinion whether the Rebels had anything to do with that.

“It wasn’t anything they did,” Mora said.

Offensive coordinator Noel Mazzone offere this: “The pressed him a lot. I thought it was a great experience for Josh. He has to learn this stuff.”

Rosen was off on more than a few throws. The Bruins came out firing, trying to stretch the Rebels defense. Rosen was unable to connect on any of his deep passes.

There were wasted opportunities as well.

UCLA reached the UNLV 29 -yard line early in the second quarter, but a one-yard loss was followed by Rosen being stuffed on a fourth-down gamble.

On their next possession, the Bruins reached the Rebels’ 37 when Rosen mishandled a snap on a third-and-one play. The four-yard loss forced UCLA to punt.

Still, Mora liked the “poise” Rosen displayed.

“He never got frustrated,” Mora said. “I was a little frustrated. He never was frustrated and that’s a great sign.”

Rosen was left wanting more after getting a heavy dose of blitzes from the Rebels.

“I got to learn to shred teams when they bring heat,” Rosen said. “It’s a feast-or-famine mentality. They may get me for a four- or five-yard loss, but if I catch you, we’re going to go quite a few yards.”

What can carry the Bruins along that learning curve are the running game and defense.

Perkins, who led the Pac-12 Conference in rushing last season, was held to 59 yards by a Virginia team loaded up to stop him. He then unloaded on the Rebels.

The Bruins scraped together a 17-0 halftime lead. Then Perkins took over. He finished with 151 yards and broke the game wide open with touchdown runs of seven and 56 yards.

“He scares a lot people,” Rosen said. “What we were able to do [passing] against Virginia was because of the fear of Paul.”

UCLA finished with 273 yards rushing even though center Jake Brendel missed the second half with a foot injury.

“Whenever we’re running the ball, getting first downs, that when we’re at our best,” Perkins said. “We feed off that tempo.”

The defense, meanwhile, fed off other things.

The Rebels gained only 237 yards, 118 of which came on three plays. UNLV completed only six of 23 passes.

UNLV had only one scoring opportunity in the first half, but the drive stalled at the UCLA 18-yard line in the first quarter. Instead of taking a field goal to try to cut the deficit to 10-3, the Rebels went with a fake. It fooled no one. Linebacker Deon Hollins chased down holder Troy Hawthorne, who flung an in complete pass.

Linebacker Kenny Young recharged the Bruins’ psyche by intercepting a pass and bolting 23 yards for a touchdown and a 17-0 lead late in the second quarter.

“We knocked them off their rhythm,” linebacker Myles Jack said. “There are times when the offense goes three and out that we have to respond.”

Chris.foster@latimes.com

Twitter: @cfosterlatimes