Duke was such an overwhelming favorite in the ACC this season that all but one voter in the conference's preseason media poll picked the Blue Devils to win the league.

And Chris Miles of WDBJ-TV in Roanoke, Va., the one voter who picked North Carolina to win, quickly explained that he had made a mistake.

For eight consecutive weeks before Jan. 24, Duke was the only ACC team ranked in The Associated Press' poll. Even after dynamic freshman point guard Kyrie Irving was injured Dec. 4, seniors Nolan Smith and Kyle Singler seemed to be exerting leadership that was so strong that no other ACC team could hope to equal the Blue Devils.

But an interesting thing happened on the way to Duke's ACC coronation. Rival North Carolina, whose five losses in its first 17 games included a 78-58 decision at Georgia Tech, found its rhythm.

Now there's a legitimate race for the ACC title. No. 5-ranked Duke (20-2, 7-1 ACC) still sits atop the conference midway through the season. The Blue Devils have won 31 in a row at home, and floundering N.C. State (12-10, 2-6) doesn't look capable of ending that streak at 6 p.m. today. But No. 23 North Carolina (16-5, 6-1) has won four in a row, with margins of 20 and 32 points against ACC opponents in its past two games.

The Tar Heels' John Henson and Tyler Zeller are imposing as low-post scorers and on the boards. Freshman Harrison Barnes finally is living up to his best-in-class hype.

North Carolina is even playing good defense, holding its past two opponents - N.C. State and Boston College - below 37 percent from the field. And guard Larry Drew II's sudden departure from the team won't significantly affect that defense. He wasn't as good defensively as many were making him out to be.

The Tar Heels have one significant hurdle to overcome to make this a two-team race. Florida State (16-6, 6-2) visits the Smith Center at 2 p.m. Sunday and has a Jan. 12 win over Duke on its resume.

Defensive stalwart Chris Singleton leads a Florida State team with the size and athletic ability that could throw Henson and Zeller off their game. Whether Florida State stays in the hunt in the ACC or North Carolina pushes the Seminoles off the pace, healthy competition is good for the conference.

And with Duke playing four of its last six ACC games on the road, there could be a chance for opponents to make up ground late in the season.

Billy Donovan has Florida back on the national radar with four wins in its last five games. The Gators play host to No. 10 Kentucky at 9 p.m. today on ESPN in one of the biggest SEC games of the season.

At 2 p.m. Sunday, No. 1 Ohio State and freshman center Jared Sullinger play at No. 18 Minnesota and muscular Trevor Mbakwe on ESPN.

ktysiac@charlotteobserver.com or 919-829-8942