ACC Power Rankings: Chizik's defense makes North Carolina a true threat

Other than the national title he won in 2010 with Auburn, 2015 stands as the most impressive season on Gene Chizik's coaching resume. After earning the title of worst defense in the ACC in 2014, North Carolina brought Chizik on as defensive coordinator, but even those who hired him didn't expect him to turn things around this quickly.

The Tar Heels are giving up 150 fewer yards per game this year than last. Opponents are averaging a yard and a half less per play and five fewer first downs. North Carolina's 17.3 points allowed per game is the 18th-best mark in the country, and their 136.5 passing yards allowed rank third.

It's more than just the numbers, too. The atmosphere in the locker room has changed. Georgia Tech took a 21-0 lead on them last week, a game in which the 2014 Tar Heels would have rolled over. This year's Tar Heels outscored the Yellow Jackets 38-10 in the remainder of the game and won their fourth straight. The 31 points they allowed in that game marked the only time this year they gave up more than 17.

In previous years, the defense has been blamed for North Carolina coming up short, but that excuse is no longer valid. Everyone knew this offense would be able to play with the best of them. Now that the defense has stepped up, expectations are high for a school that's usually waiting for basketball season this time of year.

ACC Atlantic Power Rankings

Clemson (last week: 1)

Deshaun Watson threw for 420 yards in Clemson's 34-17 win Saturday. The Tigers are a real playoff contender, but the they've been here before and know to tread lightly.

2. Florida State (last week: 2)
Speaking of big passing days, Everett Golson had a game to write home about against Louisville, throwing for 372 yards. Dalvin Cook ran for 163 as the playmakers keep getting the job done for the Seminoles.

3. Louisville (last week: 3)

2-4 isn't the way Louisville saw the first half of its season going, but the worst part of its schedule is over and a bowl game is still well within reach.

4. NC State (last week: 5)
A bye week for NC State, who, after an easy non-conference schedule, only need to win two ACC games to be bowl-eligible. Easier said than done, though, as the Wolfpack are 0-2 in the conference thus far.

5. Wake Forest (last week: 6)
Wake Forest led North Carolina after the first quarter, but that's where the good news ends. The Demon Deacons gave up 28 unanswered to close out a 50-14 loss.

6. Boston College (last week: 4)
Clemson may be one of the best teams in the country, but losing to the Tigers drops Boston College to 0-4 in the ACC.

7. Syracuse (last week: 7)
The Orange have lost two straight games they needed to win to be taken seriously in both the ACC and the bowl conversation. The schedule gets a lot tougher now.

ACC Coastal Power Rankings

1. North Carolina (last week: 2)
North Carolina scored 29 points in the second quarter of a game in which Wake Forest scored 14 points total. The Tar Heels will be ranked soon if they keep winning.

2. Duke (last week: 1)

The Blue Devils had a bye week. The stage is set for a very interesting rivalry matchup against North Carolina in three weeks.

3. Pittsburgh (last week: 3)
Pittsburgh snuck into the AP top 25 this week after beating Georgia Tech by a field goal. In September that's a quality win, but the Yellow Jackets have been losing to everyone lately.

4. Miami (last week: 4)

Miami bounced back from two straight losses with a win over Virginia Tech. Brad Kaaya defended his ACC lead in passing yards with 296, but Miami needs to develop a second dimension.

5. Virginia Tech (last week: 5)
The return of Michael Brewer was not enough to get the Hokies a win against Miami, but if he can get back into a groove, Virginia Tech can be a spoiler later in the year.

6. Virginia (last week: 7)
Virginia beat Syracuse, but that isn't saying much.

7. Georgia Tech (last week: 6)
The Yellow Jackets fooled everyone into thinking they could win the Coastal division this year. Maybe next year.