When LenDale White jumped on Twitter last weekend to rip Southern California defensive coordinator Justin Wilcox's "prevent defense," the former Trojans tailback was only seeing one part of USC's problems in finishing games lately.

Some of that criticism could have been aimed at the USC passing offense, which has not held up its end of the deal while the Trojans split their last two games against Arizona State and Arizona.

"The last two games we had opportunities to run the clock out when the other team had no timeouts, and we've got to capitalize," quarterback Cody Kessler said.

Kessler has largely played well this season, throwing for 1,565 yards and 11 touchdowns against one interception, but he was a non-factor in the fourth quarter against the Sun Devils and Wildcats, games that were ultimately decided on the final play.

Kessler was 4 of 5 for 45 yards in the fourth quarter against Arizona State, most of that production coming when he found running back Javorius Allen for 37 yards on the first play of the quarter. His final throw was a third-down bubble screen to receiver Nelson Agholor that lost 6 yards, keeping USC from running more clock and allowing Arizona State to complete a game-winning Hail Mary as time expired.

Against Arizona, Kessler was 1 of 4 for 1 yard and took a sack in the fourth quarter. His only completion came on a third-down pass into the flat for Allen on USC's final possession, though Kessler thought the call was sound.

"We liked our chances he would be on the (linebacker) and hopefully make a play, but he caught it and you can see on the film that he slipped a little bit, lost his footing," Kessler said. "Nine times out of 10 he makes that guy miss and gets 5 yards. I'd take my money on Buck anytime on that play."

USC was seemingly content to run its offense through Allen and sophomore Justin Davis, who touched the ball on 38 of its 69 offensive plays. Coach Steve Sarkisian had challenged the pair at the start of October to deliver more explosive runs. Now he has issued the same challenge for Kessler and the passing offense.

Kessler did not complete a pass for more than 25 yards against Arizona and admitted he has been hesitant unleashing his deep ball at times, exactly what his coaches are trying to coax out of him.

"(Offensive coordinator Clay) Helton had a funny comment that we've broken the ice on the interceptions, so it is all right to throw one up and see who comes down with it every once in a while," Kessler said.

Facing a Colorado defense that has surrendered 15 touchdown passes this season, third-most in the Pac-12, would seemingly offer Kessler the chance to be more aggressive this week.

But Kessler said it doesn't matter how the offense comes by those critical plays, only that it executes them.

"Whether it is a pass or a deep pass or a short run, whatever it is I want to keep our defense off the field," Kessler said.