IOWA CITY — The echoes of the jubilant crowd have long since faded from East Lansing after Iowa's shocking 32-20 loss to Michigan State on Saturday, but the sting of a third loss — and a defensive no-show, especially from the secondary — still lingers in Iowa City, 24-hour rule be damned.

"I'd be remiss if I didn't give a lot of credit to Michigan State, but it really just comes down to fundamentals," said senior linebacker Nick Jackson, who recorded 11 tackles in Saturday's loss. "That's not really a performance that we want to put out there."

The Spartans gained 468 yards from scrimmage against the Hawkeyes in Saturday's contest, and Iowa was unable to force a punt for the first time in over a decade (Ohio State, 2013).

It wasn't big plays dooming the Hawkeyes, either; the Spartans marched for 27 first downs to Iowa's 12, and commanded a near 2-to-1 advantage in time of possession with 39:44 to the Hawkeyes' 20:16.

"Bottom line is Michigan State played really well, and they deserved the win," said head coach Kirk Ferentz at his weekly press conference on Tuesday. "I think we had a solid plan but didn't do basically anything well enough to expect to win a game like that."

If there's a "down side" to being a team's best cornerback, it's that teams don't have to attack them to be successful in the pass game. To that end, cornerback Jermari Harris — the lone bright spot at corner for the Hawkeyes this season — often found himself watching as quarterback Aidan Chiles attacked cornerbacks T.J. Hall and John Nestor with impunity.

"Outside of Jermari, we have some guys [at cornerback] that are still learning on the job," said head coach Kirk Ferentz at his weekly press conference. "A lot of it is technique, a little smarter positioning or seeing the situation a little bit differently than you had on the field."

Though PFF's numbers should always be taken with some level of skepticism (as Iowa's coaches are ever eager to remind), its ratings of the Iowa defensive performance on Saturday were brutal, with the five worst game grades given to defensive backs:

Between the most recent MSU loss and a string of quality performances from opposing quarterbacks — Iowa is now 83rd in the nation in passing yards allowed per game — it certainly seems as if teams have figured out a way to attack soft spots in Iowa's base defenses.

"Yeah, I didn't know that stat either, that's not good news," Ferentz. "When you aren't playing fundamentally sound, and part is physical but also communication sometimes, and everybody being on the same page. That's what defense is all about, all 11 guys being tied on a string, if you will, and one thing complements the other. So if you get somebody out of place, you could create some voids. We've fallen victim to that. We've also fallen victim to some really good play. You think about the Ohio State receivers and trying to defend those guys."

Of course, the secondary gets a pass (pun not intended) for giving up catches to the likes of OSU's Emeka Egbuka and Jeremiah Smith, both obvious NFL-caliber talents. When true freshman Nick Marsh can go for eight catches and 113 yards on Iowa — after totaling seven catches for 115 yards in his last three games combined — it probably merits deeper scrutiny whether this version of Iowa's secondary is still being set up to succeed.

As Iowa looks for answers in the secondary with only five games left in the regular season, Harris says defensive coordinator and DB coach Phil Parker's message to his players has not changed — though it might be a bit more forceful.

"I don't think his perspective changed at all, he's just more intense, and that's what the good coaches do," said Harris. "They don't change up their philosophy midway through, they just intensify it. They're going to find a way to get through to you, but still coaching the same principles. And that's why I think our coaches are some of the best in the country, because when things hit the fan, that's when they're at their best."

As a senior leader in the secondary room, Harris also preaches consistency and focus to his teammates.

"Just continue to be consistent every day, everything you do," said Harris. "Try to be as consistent and efficient as possible: with your time, with your schoolwork, because it all correlates at the end of the day. If you're taking care of business off the field, you'll take care of business on the field."

All told, Iowa missed 19 tackles against Michigan State according to PFF, an uncharacteristically poor performance from one of the last programs in the country one would expect it from. So was it a matter of not enough effort? Trying to do too much?

"I wouldn't say there's any one specific root cause," said Jackson. "At the end of the day, it just comes back to the fundamentals, and then hats off to Michigan State."

With Northwestern coming to town, Iowa is a 14-point favorite to right the proverbial ship and come one step closer to bowl eligibility, but after getting pushed up and down the field in East Lansing on Saturday — and facing another dual-threat quarterback in Jack Lausch — nobody on the Iowa defense is taking the next challenge for granted.

"Their quarterback, he gets that thing going," said Jackson. "He can make plays in the run game, he can make plays in the pass game, he's a ball-player. Running back's physical, so they present a lot of challenges."

Harris mirrored Jackson's assessment of their next opponent. "Dual-threat quarterback, they have great athletes at the receiver position, running back position is going to pose a threat," said Harris. "So, continue to be good with our alignments and key responsibilities."

If there's any good news for the secondary, it's that defensive backs Sebastian Castro and Koen Entringer are projected to return to the field on Saturday. Castro was listed as questionable for the Michigan State game and ultimately did not play, watching the game in street clothes, and Entringer left early with a leg injury.

"They both practiced today, so I anticipate they're going to be okay," said Ferentz. "Koen, we dodged a bullet there. His injury looked like it might be a little bit more serious on Saturday. But fortunately, he'll be fine."

Iowa's tilt with the Wildcats kicks off at 2:30 PM CT on Saturday, broadcast on the Big Ten Network.