Every year, a few mind-blowing upsets occur this time of year, and every year, we are shocked when it happens. Three of the top five single game performances of the season occurred on Saturday, including the best individual game rating of the year. Oklahoma State’s blowout win against Baylor produced an SRS score of 88.5, topping Florida State’s win at Clemson by three points. Meanwhile, Arizona shocked Oregon, giving the Wildcats (82.9 score) just the third 80+ point SRS rating in a game in 2013. And in less exciting but still noteworthy news: Washington crushed Oregon State (#27 in last week’s SRS ratings) in Corvalis, 69-27.

It looks like we’re headed for a Florida State-Alabama showdown in the BCS National Championship Game. FSU’s last two games should not pose any issues: the Seminoles are rated 27 points higher than Florida, and will be a three-touchdown favorite in the ACC Championship Game. In fact, the difference between the ratings of Florida and Georgia Southern is smaller than the difference between Florida and Florida State (you can view the ratings of FCS teams here). And we’ll get to that Georgia Southern game in a minute.

For Alabama, the schedule is a little more challenging. The Tide are “only” 9 points ahead of Auburn in the SRS, but that’s a little misleading. If we remove Alabama’s games against Colorado State, Georgia State, Chattanooga, Kentucky, and Tennessee — all games the Tide won by over 21 points — their rating would jump to 64.4. For Auburn, the only team they beat by more than three touchdowns that lowered their rating was Western Carolina; do that, and the Tigers are at 52.9. That puts Alabama 11.5 points better than Auburn. The Iron Bowl is in Auburn this year, and the Tigers are 10.5 point underdogs, so perhaps the SRS is still underrating the Tide by a point or two. An SEC Championship Game against Missouri would be another tough test, but first, those Tigers must defeat Johnny Manziel and the Aggies to earn a trip to Atlanta.

Below are the SRS ratings through 13 weeks. As always, thanks to Dr. Peter Wolfe for providing the final scores for every college football game.

So where does the Georgia Southern upset over Florida rank? How does it compare to say, Arizona beating Oregon? What has been the biggest upset of the season? The table below shows the 25 biggest upsets, based on the SRS difference between the two teams. Using this metric, West Virginia’s win over Oklahoma State grades as the top upset of the year, with Georgia Southern’s shocking upset only ranking third. Here’s how to read the table, using the West Virginia line. On September 28th, West Virginia beat Oklahoma State at home, 30-21. Oklahoma State has an SRS rating of 57.2 and West Virginia of 33.3, meaning the Mountaineers were 23.8 points worse than the Cowboys.

As always, you can view the SRS ratings for each FBS team in each game here. Below are the SRS ratings for each game in week 13.