Who helped their College Football Playoff case in Week 3?

— -- Prove it. That was the theme in Week 3, when several top teams with padded stats and playoff dreams faced an upgrade in competition, revealing a more accurate snapshot of their potential this fall.

Here's a look at the playoff contenders who passed their first tests -- and who flopped:

SEC

PASS: Ole Miss offense. ESPN's Football Power Index had the Rebels ranked No. 1 and favored to beat Alabama by two points, and that was based on QB Chad Kelly and the potential for a top-10 offense this season. Alabama's front seven showed spark, but nowhere near the consistency it needed to stop the Rebels' big plays. The FPI has Ole Miss favored to win every game left on the schedule. It's time to take these guys seriously -- again.

FAIL: Alabama. The Tide struggled in all three phases of the game in the loss to Ole Miss, failing to find an identity on offense with quarterbacks Jake Coker and Cooper Bateman, fumbling the ball twice on kickoff returns, and finishing with five turnovers. We've seen Alabama struggle defensively before, but usually the Tide have an answer offensively. The SEC race has just begun, and the conference kings are already playing from behind.

PAC-12

PASS: Stanford, UCLA. The Cardinal are back in the conversation. Just like that. Stanford's offense was resuscitated by QB Kevin Hogan and looked more than capable of contending for the Pac-12 North. It was quite a turnaround after scoring just six points in its loss to Northwestern, but Stanford seems to have found its groove. UCLA needed a late interception from Myles Jack to hold off BYU, but considering how things unfolded for USC, it was a double win for the Bruins. They also learned they can come from behind to win and that they can still win even when Josh Rosen throws three first-half picks.

FAIL: USC. The Pac-12 favorite couldn't even make it past the league opener. USC isn't out of the Pac-12 race, but its margin for error has significantly decreased. USC still has five ranked opponents remaining on the schedule, including road trips to Notre Dame and Oregon.

BIG TEN

PASS: Northwestern. The Wildcats caught the nation's attention with a stingy defensive performance in their season-opening upset of Stanford, and after Saturday's win against Duke, Northwestern now has two wins over Power 5 opponents and is 3-0. Stanford's win over USC makes Northwestern's win look even better. Who says NU can't be the best team in the West?

FAIL: Ohio State's offense. It's hard to believe that Ohio State's quarterback situation has gone from a strength to a concern. Granted, the offensive line has been underwhelming, but both Cardale Jones and J.T. Barrett struggled in a too-close-for-comfort win over Northern Illinois. Ohio State had five turnovers, and Urban Meyer conceded "there might be some truth" to the notion he needs to pick a starting QB and stick with him.

BIG 12

PASS: Texas QB Jerrod Heard. No, the Longhorns aren't playoff contenders, but let's give Texas a pat on the back after what's been an abysmal start to the season. Heard set a school record with 527 total yards of offense and his third rushing touchdown brought Texas within a point with 1:11 left against Cal. A missed extra point has punctuated the season so far.

FAIL: TCU's defense. The Frogs are injured. They're depleted. But they also gave up 508 yards and 37 points to SMU, which is a much-improved team under coach Chad Morris but still shouldn't be such a scare for the Big 12's best. TCU will head to Texas Tech, which just beat Arkansas, and it's going to need to mature quickly on defense if it's going to remain in the playoff conversation.

ACC

PASS: Florida State and Clemson. It wasn't pretty, but Florida State and Clemson both won on the road against stingy defenses, keeping the league's playoff hopes alive and reasserting themselves as the teams to beat in the ACC. Clemson faced a gritty Louisville team that dropped to 0-3, and FSU beat a well-coached and disciplined Boston College team that has given the Noles fits in recent years. Neither team looked like top-four material, but a loss by either one would have dinged the league's reputation another notch.

FAIL: Georgia Tech. The road trip to Notre Dame was a huge opportunity for the Jackets to prove that they could score on ranked opponents, and possibly create some playoff buzz in the Coastal Division, but the Irish defense had an answer. Georgia Tech has a schedule difficult enough to get the selection committee's attention, but it couldn't even clear the first hurdle.

OTHERS

PASS: Notre Dame. Not only can the Irish win with backup QB DeShone Kizer, they can still be one of the top teams in the country. With the help of C.J. Prosise and Will Fuller, Kizer made a smooth transition into the leader of the Irish offense, but it was also a disciplined defensive effort that helped beat Georgia Tech.

FAIL: BYU. As far as the Cougars' playoff hopes are concerned, the loss to UCLA likely eliminated them from top-four consideration, but it's too harsh to call it a complete fail because it was a great game that went down to the wire. BYU isn't a top-four team, but it's certainly a top-25 team that has earned respect after hanging with UCLA on the road.