Clemson up to No. 2 in AP poll as Ohio State falls to No. 11; App State breaks in

Herbstreit: Ohio State has a lot of work to do (1:21)

Kirk Herbstreit joins SVP on SportsCenter to break down Ohio State's issues following a loss to Purdue. (1:21)

Clemson is back at No. 2 in The Associated Press college football poll behind top-ranked Alabama, moving up to where it started, after a convincing victory and Ohio State's first loss of the season.

The Crimson Tide are a unanimous No. 1, with all 61 first-place votes, for the first time this season. Ohio State tumbled nine spots to No. 11 after being upset by Purdue.

Coming off a lopsided win against NC State, Clemson rose one spot to replace the Buckeyes. Clemson trailed only Alabama in the preseason rankings, but a couple of close wins in September -- combined with seemingly impressive performances by other highly ranked teams -- dragged Clemson to as low as No. 4.

Notre Dame is No. 3 and LSU is No. 4, setting the stage for a top-five matchup between the Tigers and Crimson Tide in Baton Rouge, Louisiana, on Nov. 3. Both have an open date this week. Michigan rounds out the top five after beating Michigan State.

No. 25 Appalachian State is ranked in the AP poll for the first time in school history. The Mountaineers (5-1) have not lost since opening the season with an overtime defeat at Penn State.

App State transitioned to the FBS, the highest level of Division I football, in 2014 after years as an FCS power. Under former coach Jerry Moore, the Mountaineers were a regular playoff participant. The program peaked in the mid-2000s, winning three straight FCS (Division I-AA) championships from 2005 to 2007. And, most memorably, App State pulled off one of the most stunning upsets in college football history against Michigan in 2007.

Moore retired after the 2012 season and was replaced by former App State quarterback and assistant coach Scott Satterfield. The move up in class and into the Sun Belt has been practically seamless. The Mountaineers are 46-23 under Satterfield, with two Sun Belt titles. The only other Sun Belt team to ever be ranked was Troy on Nov. 13, 2016.

This season's team was expected to contend for another conference championship. A case could be made that it is exceeding even those high expectations after replacing four-year starting quarterback Taylor Lamb and much of its defensive front seven. Since falling to Penn State, the Mountaineers have outscored their opponents 231-49.

Elsewhere in the poll, No. 14 Washington State was the only big mover to rise in the rankings this week, jumping 11 spots after beating Oregon, which fell seven spots to No. 19.

No. 22 NC State fell six spots after losing for the first time this season.

No. 23 Utah is ranked for the first time this season, making it five straight years the Utes started the season unranked but moved into the rankings at some point. From 2014-16, Utah started the season outside the Top 25 but finished it ranked. Utah has won three straight, scoring at least 40 points in each game.

No. 24 Stanford is back in the rankings after falling out two weeks ago, while Michigan State and Mississippi State fell out of the rankings again after losing for the third time this season. And Cincinnati's first loss of the season, in overtime to Temple, cost the Bearcats their first ranking since 2012.