TUCSON, Ariz. _ Dorian Thompson-Robinson walked behind his teammates huddled on the sideline, clapping his hands in encouraging fashion before patting a few helmets.
Somebody else was going to have to win the game for UCLA after its starting quarterback went down Saturday night at Arizona Stadium.
Thompson-Robinson had suffered an apparent ankle injury late in the third quarter against Arizona, turning the game into a battle of backups after the Wildcats played the entire game without star quarterback Khalil Tate.
UCLA's Austin Burton needed to drive the Bruins nearly the length of the field for a tying field goal or a go-ahead score that would give them sole possession of first place in the Pac-12 South Division.
They got neither.
Burton engineered a drive that put his team well within field-goal range, but J.J. Molson's 39-yard attempt sailed wide right and the Wildcats held on for a 20-17 victory that sapped all of the Bruins' momentum from their crazy comeback last weekend over Washington State.
Molson had made a field goal from the same distance moments earlier, but the Wildcats called a timeout before he could get off the kick. Molson has made only two of five field goals this season, including a 37-yarder Saturday.
Burton competed admirably in his college debut, completing five of nine passes for 48 yards. It wasn't enough.
He had thrown a few hurried warmup passes late in the third quarter after Thompson-Robinson took a big hit, forcing him to limp off the field and crouch on the sideline.
All Burton had to do to energize the Bruins' offense was hand the ball off to running back Joshua Kelley, who juked his way for 36 yards down to the Arizona three-yard line. On the next play, Kelley plunged into the end zone to give his team a 17-13 advantage.
But Arizona retook the lead after converting a fourth and one on its next drive thanks to a questionable referee spot. The Wildcats cashed in when running back Gary Brightwell broke two tackles on a 10-yard touchdown run that provided the game's final points.
The Bruins (1-4 overall, 1-1 Pac-12) looked nothing like the offensive juggernaut that had dropped 50 points on Washington State last weekend in a span of less than 19 minutes to complete the second-biggest comeback in school history. They reverted to their early-season habit of looking unstoppable on the game's opening drive and then sputtering for long stretches.
A bad game for UCLA's secondary got exponentially worse early in the third quarter when Arizona running back Darrius Smith came out of the backfield, caught a pass without a defender in the vicinity at the Wildcats' 47-yard line and ran untouched down the sideline for a 75-yard touchdown.
The all-too-easy score gave Arizona (3-1, 1-0) a 13-10 lead, its first advantage of the game,
Arizona true freshman quarterback Grant Gunnell, making his first college start after having appeared only in mop-up duty earlier this month against Northern Arizona, completed 29 of 44 passes for 352 yards with one touchdown.
Before he went down, Thompson-Robinson could not sustain his red-hot play from late in the game against the Cougars beyond his team's first possession. He completed 17 of 33 passes for 180 yards and a touchdown to go with an interception on a pass thrown directly into the arms of Arizona cornerback Lorenzo Burns.
Thompson-Robinson had been heavily involved in all the big plays on the Bruins' opening drive, including runs of 14 and 26 yards in which he showed off his ability to juke defenders. He also connected with tight end Matt Lynch in the back of the end zone for a two-yard touchdown, the converted quarterback's first college catch.
The Bruins enjoyed far lesser results on their next drive. Kelley ran for one yard on third and two before coach Chip Kelly had his players hurry to the line of scrimmage, facing a fourth and one at their own 36-yard line. Kelley took the handoff and tried to leap over a pack of defenders but couldn't get the yard he needed, giving the ball back to the Wildcats.
UCLA gained only 185 yards in the first half, its ragged play reflecting a team playing its second consecutive road game against an opponent coming off an open week.
Those extra days off weren't sufficient to help Tate fully recover from the hamstring injury he suffered late in the Wildcats' game against Texas Tech on Sept. 14. It was the second consecutive season that Tate didn't play against the Bruins after he missed last year's game because of a sore ankle.
Taylor missed the game because of a lingering lower leg injury, depriving the Wildcats of the 148.6 rushing yards that Tate and Taylor combined to average over the season's first three games.
The way everything turned out, they were just fine.
