College Football Playoff takeaways: What we've learned so far, and what's to come

Unranked NC State stuns Clemson in 2OT (0:56)

Clemson loses to an unranked team for the first time since 2017 as NC State pulls off a 27-21 win in double overtime. (0:56)

September was full of surprises, opening the door for unheralded teams like Arkansas, Iowa and Michigan, while slamming it shut on perennial power Clemson.

The first of six College Football Playoff rankings isn't revealed until Nov. 2, following an October packed with conference games that will start to reveal which teams' playoff aspirations are legitimate. There are a handful of teams, like Notre Dame and Oklahoma, that don't look like top-four material, but also might not need to finish the season undefeated.

Here's a look at four lessons learned after one month, and four storylines that will impact the playoff in October.

What September taught us

1. So long, ACC. It's probably premature -- technically -- to write off an entire Power 5 conference in September, but when Wake Forest and Boston College are the only undefeated teams remaining, it's safe to say the ACC doesn't have a playoff contender. Wake and BC are improved, respectable teams, but they're not elite, and their schedules don't give them any opportunities to prove otherwise.