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Sports on Earth Week 9 stories: Lion tamers: Barrett, OSU come up B1G | Rising Cyclones topple TCU | The Khalil Tate show rolls on

1. Two top-four losses set the stage for first playoff top 25.

With the first College Football Playoff rankings set to be revealed on Tuesday, the pecking order first got a bit of a shake-up on Saturday. Two of the top four teams in the AP poll -- No. 2 Penn State and No. 4 TCU -- lost in games that were surprising in different ways. Fellow unbeaten No. 17 South Florida also lost, falling 28-24 at home to Houston, and No. 16 Michigan State added a second loss and knocked itself out of the longshot playoff chase with a 39-31 triple-OT defeat at Northwestern.

In the game of the day -- perhaps the game of the year -- No. 6 Ohio State beat the Nittany Lions 39-38. A win by the Buckeyes, a touchdown favorite on their home field, was not surprising. How they did it was certainly surprising: After a mistake-filled first three quarters, they erased 15-point deficit at the start of the fourth quarter. (They also trailed 14-0 within four minutes of the game starting and were down by as many as 18 in the second quarter.) Their defensive front wore down Penn State's offensive line and bottled up Saquon Barkley, who returned the opening kickoff for a touchdown but had no room to run in the second half. And QB J.T. Barrett played the best game of his career, completing 33 of 39 passes for 328 yards and four TDs in a confident, masterful effort against what had been a dominant Penn State pass defense the first seven games.

The other top-four loss was an actual upset, but then again maybe we should be expecting this from Iowa State now. The Cyclones started October by upsetting then-No. 3 Oklahoma. They entered the AP poll last week for the first time since 2005, then ruined TCU's undefeated season on Saturday at home. The Cyclones won 14-7, as they led 14-0 at halftime, didn't allow an offensive touchdown and took advantage of TCU's many mistakes, which included three turnovers and 11 penalties. The surging Cyclones are doing their best to disrupt the Big 12 race and potentially knock the conference out of the playoff.

Both Penn State and TCU are still alive in the playoff hunt at 7-1, but their candidacies took significant hits that will shuffle them toward the back half of the top 10 on Tuesday. There are five undefeated teams remaining: Alabama, Georgia and Wisconsin are 8-0. Miami and UCF are 7-0. Given that it beat Notre Dame -- a top-10 team that crushed N.C. State on Saturday -- and is coming off a 42-7 win over Florida, there's a chance that Georgia, not Alabama, will be the selection committee's No. 1 team on Tuesday. Despite Alabama's lack of wins over strong opponents (Florida State continues to hurt the Tide's resume), expect both Georgia and Bama in the first top four.

Miami and Wisconsin are unbeaten but will likely be outside the top four, leaving a debate between 7-1 Notre Dame, Oklahoma, Ohio State and Clemson for the final two top-four spots. Of those teams, Notre Dame has the "best" loss, falling by only one to Georgia. Oklahoma has the best win, beating Ohio State by 15 in Columbus (a result that seems to have been forgotten by many poll voters).

2. Hot seat talk in the SEC continues to grow.

Not only has Georgia become a playoff contender in Kirby Smart's second season, but it has also done significant damage to the coaching tenures of both Tennessee's Butch Jones and Florida's Jim McElwain, the Bulldogs' chief rivals in the SEC East.

After already beating the Vols 41-0, Georgia crushed Florida 42-7 in Jacksonville on Saturday. The Bulldogs got off to a fast start, attempted seven passes, rushed for 292 yards and were never in danger of this being anything but a blowout. The win happened amid reports, including from ESPN, that Florida administrators are talking about trying to fire McElwain for cause. It's yet another bizarre turn of events in the tenure of a coach who won the SEC East his first two seasons but hasn't been a good fit in Gainesville. McElwain has yet to improve Florida's stagnant offense. This season got off to a terrible start with a long list of suspensions. And, last week, McElwain spoke about the team receiving death threats but didn't provide any details to the media or to the university, adding to a growing rift. On the field, Florida is now 3-4, and suddenly it appears that McElwain may not make it through his third season.

Jones may also have reached the end of his time at Tennessee. The Vols finally scored an offensive touchdown for the first time since Sept. 23 against UMass, but they lost to Kentucky on an 11-yard Stephen Johnson touchdown run with 33 seconds left. A last-play Hail Mary was caught … but a few yards short of the end zone. It's just the second Tennessee loss to Kentucky in their past 33 meetings, and it happened even though the Vols won the turnover battle 4-0, as they settled for six field goal attempts (making three). Tennessee is 3-5 overall and 0-5 in the SEC.

Arkansas' Bret Bielema managed to escape massive scrutiny this week when the Razorbacks beat Ole Miss 38-37 after falling behind 31-7 in the second quarter. Texas A&M coach Kevin Sumlin wasn't so lucky. After trying to pull himself off the hot seat with three tight SEC wins in four games, Sumlin and the Aggies hit a wall in a 35-14 home loss to Mississippi State. It was Texas A&M's third loss to the Bulldogs in the past four years.

3. Notre Dame couldn't have started its difficult second half any better.

Notre Dame went 5-1 in the first half of the season, with a 20-19 loss to Georgia and a 38-18 win over Michigan State standing out as the highlights on the schedule. There was talk of the Fighting Irish becoming a playoff contender, but it wasn't easy to take seriously because of how difficult their second-half schedule looked. November is still a daunting task -- Wake Forest, at Miami, Navy, at Stanford -- but the Irish have gotten off to an unbelievable start to the second half of the season.

After demolishing USC 49-14 last week, Notre Dame demolished N.C. State 35-14 this week. Although Bradley Chubb made an impact for the Wolfpack early, Notre Dame's powerful offensive line and running game ultimately won the matchup against Chubb and N.C. State's vaunted defensive line. The Irish trailed 14-7 in the second quarter but scored the game's final 28 points, as RB Josh Adams continued his Heisman campaign with 27 carries for 202 yards, including a 77-yard touchdown run. That long TD combined with a 69-yard pick-six by Julian Love -- on N.C. State QB Ryan Finley's first interception of the season -- broke the game open in the third quarter.

With two huge hurdles cleared, Notre Dame has a case for a top-four ranking entering a difficult November.

4. Iowa State's rise creates a wild Big 12 race.

The race will probably sort itself out. Oklahoma still has to play Oklahoma State and TCU the next two weeks, and Oklahoma State goes to Iowa State on Nov. 11. Other teams are capable of taking down the current conference leaders, too.

Nevertheless, it's hard not to look at the Big 12 and see a bit of chaos right now, especially with a 10th conference game -- the return of the conference championship game -- for whomever emerges as the top two teams in the standings. Entering November, Iowa State, TCU, Oklahoma and Oklahoma State are all 4-1 in the Big 12. Iowa State has two losses overall (it lost a heartbreaker to Iowa), and the other three have only one loss each. Iowa State provided TCU and Oklahoma with those only losses.

Iowa State -- which won a total of 11 games the past four seasons and hasn't had a winning record since 2009 -- is in the best position in the race for a spot in the Big 12 title game, already owning wins over two of the three teams it is tied with. TCU, Oklahoma and Oklahoma State all still have legitimate playoff hopes, but none can afford another loss. The Big 12 stands a good chance of knocking itself out of the playoff, but at least if it does, the race to the conference title game is shaping up to be a thrilling one.

5. Heisman Trophy race takes a turn entering November.

Few Heisman races ever have much clarity at the end of October, but after the events of this weekend, it's quite clear that the race is wide-open in the final month. Presumed favorite Saquon Barkley returned the opening kickoff for a touchdown at Ohio State, then had a 36-yard touchdown run. But he was totally shut down in the second half -- he had little, if any, room to run -- and finished with 21 carries for 44 yards and four catches for 23 yards in Penn State's heartbreaking loss. Stanford running back Bryce Love, who has been setting a torrid statistical pace, didn't play in the Cardinal's 15-14 win over Oregon State on Thursday because of an ankle injury.

Both star tailbacks are still top candidates, but any gap they had has been significantly reduced. Oklahoma QB Baker Mayfield is still right in the thick of the race. Ohio State QB J.T. Barrett re-announced his candidacy with a sterling fourth quarter against Penn State. Notre Dame's Josh Adams had another big game to give himself 1,169 rushing yards in eight games. And so on. Even a player who didn't start in September is going to pick up some sleeper buzz: Arizona QB Khalil Tate, a big-play machine who rushed for 840 yards in four October games. He had 421 yards of total offense in Arizona's 58-37 win over No. 15 Washington State late Saturday night.

We learned a lot on Saturday. We've learned a lot through nine weeks. But as the calendar flips to November, the college football season is shaping up as hoped: an open playoff race and an open Heisman race, with an unpredictable finish coming for both.

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