You could understand if Nebraska defensive coordinator John Papuchis is suffering from UCLA post-traumatic stress disorder this week, seeing blue and gold flashes in his nightmares.

Neither Papuchis nor any member of Big Red Nation needs any reminders of what happened the last time the Huskers and Bruins met. The numbers stick out like a bad memory: UCLA put up 653 total yards in a 36-30 win at the Rose Bowl in Week 2 last season, drawing a giant red circle around the cracks in Papuchis' defense.

"Coming out of that game, it became clear that we did have some deficiencies," Papuchis told ESPN.com. "I knew that the rest of the season, we were going to have mask them as best we possibly could to make sure they didn't get exposed again."

You know what happened next. Nebraska did a decent job hiding its flaws in the regular season, save for a trip to Columbus, before Wisconsin ripped open the wounds in the Big Ten title game. Almost all offseason conversations in Lincoln centered around how Papuchis and head coach Bo Pelini would fix that defense.

Now here comes UCLA again, minus a few key players like star tailback Johnathan Franklin but still boasting top-notch playmakers such as quarterback Brett Hundley (358 total yards, 4 touchdowns in last year's win). Nebraska hopes its defense is much different this time around.

Many of the names, for sure, have changed. The Huskers have seven new starters on defense, and nine players in their front-seven rotation have made their major college debuts in the past two weeks. That includes freshmen starting linebackers Josh Banderas and Nathan Gerry and defensive end Randy Gregory, a junior college transfer.

Opening returns weren't great, as Wyoming turned in a very Bruins-like showing behind another mobile quarterback named Brett (Smith) and piled up 602 yards, but Nebraska pulled out a 37-34 squeaker. Last week, though, Nebraska held Southern Miss to just 284 yards and forced four turnovers in a 56-13 victory.

"I think that [Wyoming] experience was tremendous for those guys," Papuchis said. "Just the experience of being out there, I think, settled a lot of nerves. We were tenfold better [in Week 2], and I think that was a better indication of what this defense is going to be about -- an athletic and fast group with a chance to be dynamic."

Speed, especially in the front seven, was something last year's senior-laden defense lacked. Pelini has said he made a mistake in not throwing some of this year's redshirt freshmen on the field last season to help. That weakness first became particularly glaring against the Bruins, who didn't run a lot of complicated sets last season, and still don't. They focus on getting the ball to their running backs and receivers to create one-on-one matchups in the open field.

In last year's matchup, Nebraska lost far too many of those battles. Pelini estimated that nearly 300 of UCLA's yards came after first contact with a Huskers defender. Guys like Franklin and receiver Shaq Evans often had Nebraska players reaching for air.

Papuchis said he notices a marked improvement in his defense's quickness, especially in the front seven with guys like Gregory, Avery Moss, Greg McMullen and Zaire Anderson.

"We've incorporated a lot more speed," senior defensive back Ciante Evans said. "Those guys can run sideline to sideline, and I think that's very helpful. It makes it easier to make plays."

The question, of course, is not just whether Nebraska defenders can beat UCLA skill players to a spot, but also whether they can wrap them up. And the Bruins are surely going to target and test young guys like Banderas and Gerry, who were in high school just a few months ago.

"One thing I like about those guys is that, to this point so far, the moments haven't been too big for them," Papuchis said.

Another benefit of that speed, Pelini said, is that more guys will be running toward and getting to the ball, rather than leaving a Husker on an island to make a tackle. Both Wyoming and Southern Miss featured spread offenses with similarities to UCLA, and the Nebraska defense swarmed to the ball much better from Week 1 to Week 2.

It may be unfair to judge a defense this young on its performance against a talented and veteran Bruins offense. But Nebraska fans and observers have been waiting for this game to use as a litmus test for the defensive progress.

Papuchis and Pelini, like their players, have insisted this week that winning or losing provides the ultimate judgment. If the Bruins put up big stats but Nebraska gets the win, they say, good enough.

Even if it's another 653-yard day?

"I wouldn't be happy with it," Evans said, "but I'd take it."

It would sure beat another case of UCLA PTSD.