His team finally holding some momentum after so much struggle, UCLA coach Chip Kelly had a decision to make early in the fourth quarter.

The Bruins had the ball at Arizona State’s two-yard line, facing fourth and one while trailing the Sun Devils by nine.

Should Kelly go for a touchdown or a field goal?

He went for seven points. He got zero.

On the play that essentially clinched the No. 20 Bruins’ 42-23 loss Saturday night at the Rose Bowl, UCLA quarterback Dorian Thompson-Robinson faked a handoff to running back Zach Charbonnet and tried to cut outside.

Thompson-Robinson didn’t make it, getting wrapped up by defensive back Eric Gentry for a one-yard loss. The second-guessing could begin after the end of the Bruins’ bid to take sole possession of first place in the Pac-12 South.

That belongs to the Sun Devils (4-1, 2-0 Pac-12) after they throttled the Bruins (3-2, 1-1) with one big play after another, winning handily despite running only 51 plays to UCLA’s 83.

The problem for the Bruins was that many of those plays went for massive yardage, Arizona State rolling up 458 yards and averaging nine yards per play while shutting out UCLA in the second half.

A big performance by tight end Greg Dulcich (nine catches for 136 yards) and solid play from Thompson-Robinson (235 yards passing, 93 yards rushing) couldn’t prop up a shaky defense or make up for a litany of errors that included two holding penalties on left tackle Sean Rhyan and a missed field-goal attempt in addition to the failed fourth down.

UCLA entered the fourth quarter trailing 32-23 and needing some defensive stops.

The Bruins appeared to have bottled up Arizona State running back Rachaad White early in the third quarter before White spun outside and outran defenders on a 49-yard touchdown that he completed by extending the ball over the goal line. The Sun Devils’ DeaMonte Trayanum ran in the two-point conversion to extend his team’s advantage to 32-23.

Arizona State ran through the UCLA secondary on the way to a 24-23 halftime lead that came courtesy of two big pass plays in the second quarter.

The Bruins defensive backs failed to bring down Sun Devils receiver Ricky Pearsall after he converted a short pass into a 65-yard touchdown to tie it at 17-17.

Pearsall victimized UCLA again a few minutes later, beating Elisha Guidry on a 54-yard touchdown that nudged the Sun Devils into a 24-20 lead.

The Sun Devils would have taken that advantage into halftime except for a poor decision in the final seconds. D.J. Taylor tried to field a punt that bounced toward him inside the 15-yard line, the ball deflecting off his body and recovered by UCLA’s Kain Medrano at the Arizona State eight-yard line with four seconds left.

Kelly elected to send out Nicholas Barr-Mira to kick a 26-yard field goal that pulled his team to within one.

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