Among the various defensive struggles that have caused Kansas University football fans displeasure this fall - a sub-par pass rush, a struggling and injury-bitten secondary - a great deal of groaning has been targeted at the lack of bite from the team's linebackers, a unit tapped by many preseason college football magazines as one of the best in the land.

While the jeers may or may not be warranted, Saturday's performance against Iowa State should, at the least, temporarily put that sentiment on hold. In arguably its most complete performance of the season, the unit combined for 23 tackles, including a sack and four tackles-for-loss, helping to hold Iowa State scoreless in its first five drives of the second half in a 35-33 comeback victory.

"I think there was significant progress at the linebacking position in the Iowa State game, especially in the second half," Kansas coach Mark Mangino said. "... I think as a unit there's some things we still need to clean up a little bit, but I think we're improving and getting better in that area."

Entering the season, the linebackers - Joe Mortensen, Mike Rivera and James Holt - were expected to be the anchor of a defensive unit that returned nine of 11 starters. These days, however, with a defensive line that is routinely a step slow and a secondary that looks more shaky with each passing week, the linebacking corps could prove to be even more integral than originally expected.

"There's some things that have changed (since 2007)," Mangino said, possibly alluding to the loss of All-Americans Aqib Talib (cornerback) and James McClinton (defensive tackle). "The dynamic around them has changed a little bit, and they have to take more responsibilities, perhaps, than they did a year ago."

Mortensen and Holt contributed eight tackles apiece against the Cyclones, while Rivera, who was removed from the staring lineup against Sam Houston for what Mangino called a lack of production, returned with vigor Saturday against the Cyclones.

In finishing with a season-high seven tackles, Rivera breathed life into a linebacking corps that - despite its preseason hype - hadn't done much to stand out throughout the first four games of the season.

"They got a couple quick scores on us, two field goals, and we were just (saying), 'Next play. We've got to look to the next play,'" said Rivera of the defense's mentality Saturday. "''We gotta do something big. We gotta make some big plays, big tackles, get a turnover, get an interception.'"

Of the positives that can be taken away from the performance against ISU, Rivera's likely re-entrance into a starting role ranks high. What should also be encouraging to those with Jayhawks inclinations is that, entering a brutal three-game stretch in which they'll face two of the nation's top seven teams, the linebacker corps appears to be coming to life at the right time.

"We certainly expect those guys to play well because they're veteran players," Mangino said. "... (And) I think they're getting better in that area."

Sharp better when tired?: In a somewhat puzzling description of his 187-total-yard, two-touchdown performance against Iowa State, running back Jake Sharp implied following Saturday's game that he plays better when tired.

"It was great to actually get tired," Sharp said after rushing for 79 yards and a touchdown and catching three passes for 107 yards and another score against the Cyclones. "It seems like when I get tired, things slow down and I feel more comfortable."

Told of Sharp's theory Sunday night, Mangino chuckled.

"I think that's an interesting observation on his part," said the coach. "I've never really had a player tell me he plays better tired. But if that's the case, we can run him around the track outside here at the stadium before the game if that will help."

KU deficits rare: It used to be the Kansas football team would fall behind early and try - with varying degrees of success - to catch up.

Lately, it hasn't needed to comeback all that often.

With the exception of Saturday's 20-0 deficit entering the second half, which paved the way for their third-biggest comeback in school history, the Jayhakws recently have managed to take an early lead and then hang onto it.

Kansas trailed in just four games in 2007 - three of which they came back to win - and, with the exception of a loss to Missouri, never were down by more than seven points.

While Mangino said Sunday that he appreciated the tenacity with which his team battled back, he also said his initial goal is not to fall in a hole to begin with.

"I prefer not to come back," Mangino said. "I prefer to be ahead the whole time, but that's not the reality of things. Our kids here fight and compete. They play right to the last play of every game, and I think yesterday showed that this team has character and that when they face adversity, they're not going to give in."

Harper shaky in return: Kendrick Harper, a senior cornerback out of Hartwell, Ga., endured a somewhat shaky return in his first game since leaving the team's Sept. 6 game against Louisiana Tech on a stretcher.

On multiple occasions Saturday, ISU quarterback Austen Arnaud picked on Harper, including on the Cyclones' potential game-winning drive late in the fourth quarter.

"Kendrick probably needed to get a game under his belt to get in game condition," Mangino said. "You can practice and simulate things on the practice field every day, but the tempo and the speed and the intensity of the game is a different animal."

Parish a part of line rotation: Although true freshman tackle Darius Parish is not yet a major factor on the Jayhawks' defensive line, recent developments suggest he's being groomed to become one.

Although he didn't record a tackle against Iowa State, Parish was part of the Jayhawks' defensive-line rotation and has been throughout much of the season.

"We're trying to not throw him to the wolves, so to speak, but rotate him in enough to give some other guys a break," said Mangino, who estimated that Parish has taken between eight and 15 snaps per game so far this year. "I think the more we can rotate guys at the defensive tackle and defensive end position, the better chance we have to play at a fast pace and a high tempo."