One night removed from watching his defense give up a season-worst 649 yards of total offense, UCLA head coach Chip Kelly reiterated Sunday that the performance wasn’t about a lack of effort.

The No. 17-ranked Bruins, on a short week as they prepare for Friday’s regular-season finale at California, had no answer for USC quarterback Caleb Williams in a 48-45 loss to their rivals at the Rose Bowl.

Williams himself accounted for 503 yards and three touchdowns, including a career-high 470 yards passing while connecting on 32 of 43 throws.

It was another rough contest for a UCLA defense that allowed 545 yards in a loss at Oregon and has struggled mightily against potent offenses. The team’s three losses have all come against three of the top 20 offenses in the country, including top-three units in USC (second) and Oregon (third).

The secondary, in particular, has been picked apart and was without starting cornerback Devin Kirkwood (left hand). Trojans wide receiver Jordan Addison, last season’s Biletnikoff Award winner, took advantage and had 11 catches for 178 yards — including a 35-yard touchdown.