Forget style points; Week 4 was all about survival

There are five former head coaches on the College Football Playoff selection committee and five athletic directors, all of whom can appreciate how difficult it is to win a conference road game.

No. 4 Penn State is less likely to be penalized for winning a close game at unranked Iowa than it is to be rewarded for finding a way to win. That's what Week 4 was all about: survival.

"They made us earn it," Penn State coach James Franklin said after his team's 21-19 win that was decided on the final play as the clock expired.

Four of the top five teams -- No. 2 Clemson, No. 3 Oklahoma, Penn State and No. 5 USC -- all had to overcome miscues and relentless opponents in order to stay undefeated. No. 8 Michigan lost starting quarterback Wilton Speight to an injury but still left Purdue with a win.

"They can win in the late rounds," coach Jim Harbaugh said, according to The Associated Press. "That's a great thing to learn about your ballclub. You never know quite what the character is. Things get tough, and a lot of people start groping for alternatives. Our guys dug deep and finished them off."

Here's a look at where each of those CFP contenders stumbled on Saturday, and whether or not fans should sound the alarm:

No. 2 Clemson (beat Boston College 34-7)

What went wrong: Turnovers and a quiet passing game.

The Tigers were tied 7-7 with Boston College in the fourth quarter before exploding to score four touchdowns in the final 12 minutes. Rookie QB Kelly Bryant's passing game finally exhibited some flaws as he threw two interceptions and no touchdowns, but he helped compensate for it with two rushing touchdowns and 106 rushing yards.

"We're battle-tested, and we had our nose bloodied today," coach Dabo Swinney said, "but at the end of the day, we came away with the win. This game was a challenge, but it's going to make us better."

Level of concern: low

Here's the good news: Even when the passing game wasn't hitting on all cylinders, the running game took over. The concern? Clemson has to travel to Virginia Tech this week, one of the toughest venues in the ACC, and traditionally one of the stingiest defenses under longtime coordinator Bud Foster. It's the kind of opportunistic defense that can force Bryant into similar mistakes and create a short field for the Hokies' offense.

Clemson's defense is elite, though, and was the difference in wins over Auburn and Louisville. With Florida State now 0-2, Clemson's spot atop the ACC Atlantic is even more solid.

No. 3 Oklahoma (beat Baylor 49-41)

What went wrong: The pass defense.

This was the first time the Sooners' defense was really exposed, and it surprisingly came against a winless Baylor team. Overall, OU allowed Baylor 523 yards of total offense, and the Bears converted on both of their fourth-down attempts. Baylor quarterback Zach Smith had 463 passing yards, including touchdowns of 71 and 72 yards.

Level of concern: medium

Oklahoma has until Nov. 4, when it faces Mason Rudolph and Oklahoma State, to fix the kinks in the passing defense. The good news for OU is that Oklahoma State already lost to TCU. The bad news? TCU looked really good and it played strong defense against elite competition, unlike OU. There's a big bull's-eye that comes with being the best, and even winless Baylor had its sights set on the target.

Don't forget, this was first-year coach Lincoln Riley's first Big 12 win as the Sooners' head coach. Quarterback Baker Mayfield still hasn't thrown an interception, and OU's running back rotation continues to evolve. ESPN's Football Power Index still projects the Sooners to win each of their remaining games.

No. 4 Penn State (beat Iowa 21-19)

What went wrong: This one is a head-scratcher. Penn State outgained Iowa 219-54 in yardage in the first half and trailed 7-5.

More than anything, this was the first time all season Penn State had really been tested (it was the first time all season it trailed in a game), and it came on the road in a hostile environment with a history of upsets. It was less about what Penn State couldn't do, and more about Iowa's resolve and defense. As good as Trace McSorley is, his interception late in the second quarter led to an Iowa touchdown.

Level of concern: low

With the dynamic duo of McSorley and running back Saquon Barkley -- whose Heisman hurdle and school-record 358 all-purpose yards will continue to be replayed until the December ceremony in New York -- Penn State maintained the wiggle room it needs for the challenging schedule ahead. The Nittany Lions' toughest stretch comes with a game against No. 8 Michigan on Oct. 21 followed by a road trip to Columbus on Oct. 28, both of which come before the first CFP ranking is revealed on Oct. 31. Because it escaped Iowa with a win, though, it maintains some margin for error.

No. 5 USC (beat Cal 30-20)

What went wrong: Sam Darnold was missing his Heisman form.

The USC offense goes as Darnold goes, and it's been just good enough. It hasn't helped that USC's running game wasn't as explosive without Ronald Jones II, which puts more pressure on the passing game. Darnold was 0-for-8 on passes thrown at least 15 yards beyond the line of scrimmage, according to ESPN's Stats & Information. It was his first career start without a completion at least 15 yards downfield.

"It's 100 percent my fault," Darnold said after the game. "I'm not getting the ball out far enough on deep routes or whether it's balls being tipped, not seeing the D-linemen and him getting a big paw on the ball to tip it in the air."

The defense had six takeaways, but the game was still tied at 13 in the fourth quarter.

Level of concern: medium

Don't forget USC was coming off an emotional double-overtime win against Texas. Cal also deserves some credit for the quick improvements it has made under new coach Justin Wilcox. USC has the talent to keep finding ways to win, but it has to be better and more consistent on offense. USC is 0-for-5 on fourth downs this season, and was just 6-of-15 on third downs against Cal. Now it has to turn around on Friday and travel to Washington State, which is also undefeated. In order to keep pace with coach Mike Leach and QB Luke Falk, Darnold is going to have to make better decisions and eliminate the turnovers.

No. 8 Michigan (beat Purdue 28-10)

What went wrong: It was another sluggish first-half performance for the offense, as the Wolverines punted on five of their seven drives, averaged just 3.7 yards per play and had 131 total yards. They trailed 10-7 at the half.

With what Harbaugh described as a "soft tissue" injury for Speight, and the respectable performance of his backup, John O'Korn, the Wolverines are still searching for their offensive identity.

Level of concern: medium

What's the extent of Speight's injury, and even if he can return, will he? Or Will Harbaugh turn the offense over to O'Korn, who helped guide the Wolverines to a perfect 3-for-3 in the red zone in the second half? The defense has championship-caliber potential, but it has to sustain it against three top-10 opponents in Penn State, No. 9 Wisconsin and No. 10 Ohio State. The Wolverines had five sacks, held the Boilermakers to just 30 rushing yards and kept them scoreless in the second half. Can Michigan do that against the likes of Barkley? Alex Hornibrook? J.T. Barrett?