CHAPEL HILL, N.C. -- Cetera DeGraffenreid didn't let North Carolina's month of frustration end with just more of the same.
Instead, the young Tar Heels are heading into the Atlantic Coast Conference tournament with a jolt of confidence after their biggest win of the season.
DeGraffenreid scored 20 of her 22 points in the second half to help North Carolina upset No. 6 Duke 64-54 on Sunday and earn a needed victory for their shaky NCAA tournament hopes.
Waltiea Rolle added 12 points, seven rebounds and six blocks for the Tar Heels (18-10, 6-8 Atlantic Coast Conference), who pushed ahead for good in the final 10 minutes of a game that was short on composure but had plenty of tension and physical play.
North Carolina had lost seven of eight games, including a 28-point loss at Duke's Cameron Indoor Stadium on Feb. 8 that had coach Sylvia Hatchell lamenting her team's inability to match the Blue Devils' toughness. But when this one was over, her players mobbed each other on the court while several students and fans ran on to join them.
With the win, the Tar Heels earned the eighth seed for the ACC tournament and will meet ninth-seeded Maryland in Thursday's first round in what could be an NCAA play-in game. The winner would face the Blue Devils in Friday's quarterfinals.
"I think we'll probably have to win a few more in the ACC tournament," Hatchell said. "I'm hoping this will get us in, but I don't know."
Three weeks after being outrebounded 52-28 by the Blue Devils, North Carolina fought Duke to nearly even on the boards while blocking 11 shots. The Tar Heels also overcame a whopping 30 turnovers that led to 25 points for the Blue Devils and 38 percent shooting.
"We knew that if we had a chance we had to match their physicality out there," Hatchell said. "That's what I challenged the players to do, to just match them, because they did pretty much manhandle us over at Cameron."
At the least, North Carolina had a toughness and resiliency it hadn't shown in a while. The Tar Heels lost Rolle and Chay Shegog to fouls within a minute of each other in the second half, and also lost freshman Cierra Robertson-Warren when she was ejected with about 13 minutes left for hitting Duke's Karima Christmas with an elbow near the jaw during a tussle on a rebound.
But the Tar Heels got 11 points from She'la White, while senior Trinity Bursey turned in some valuable minutes in her final home game -- including with her defense against Duke's Jasmine Thomas. They also held the Blue Devils (24-5, 12-2) without a field goal for the final 6 minutes.
DeGraffenreid scored 12 of North Carolina's 14 points during one second-half stretch and went 13-for-15 at the foul line in the second half.
"We just enabled her completely," Duke coach Joanne P. McCallie said. "Give her credit for being a penetrating, North-South guard, but we didn't do too much to make her go East-West."
Christmas scored 14 points to lead the Blue Devils, but Duke -- which had already earned the top seed in the ACC tournament -- shot a season-low 26 percent and couldn't take advantage of countless offensive rebounds or turnovers from the Tar Heels.
Thomas managed 11 points on just 4 for 16 shooting for Duke, which managed just five second-chance points despite grabbing 25 offensive boards.
"You've got to let this game go," Duke senior Joy Cheek said, "but we can't play like this again."
The Blue Devils could have earned the league crown outright with a victory. Instead, they shared it with Florida State, who they beat Jan. 29 .
DeGraffenreid pushed the Tar Heels ahead for good when she stole the ball from Shay Selby and raced in for a layup to make it 45-44 with 10:22 left.
She ended her flurry by scoring on a transition layup despite getting hit in the forehead by Selby, then hitting the free throw for the three-point play, making it 57-51 with 3:58 left.
"The coaches kept telling us to take it to the basket, take it to the basket," DeGraffenreid said. "A lot of getting to the rim and getting on the fast break was my teammates getting the rebounds and getting it out. We did that well in the second half."
That was as close as the Blue Devils would get in the final minutes, missing shot after shot while the Tar Heels made enough free throws down the stretch to stay in control.