Nov. 01, 2013 @ 01:09 PM

If North Carolina hopes to win a second straight NCAA title, it can’t rely solely on Crystal Dunn and Kealia Ohai for its offense.

So the Tar Heels took a big step in their title defense Thursday against rival Duke, and just in time for the postseason.

Substitutes Cameron Castleberry and Brooke Elby scored their first goals of the season and Summer Green improved to 4-for-4 on penalty shots as the Tar Heels won 3-0 at Fetzer Field in the regular-season finale for both teams.

Before Thursday, Dunn and Ohai had combined for 20 of UNC’s 35 goals.

“These are two incredible players, Dunn and Ohai, but very good coaches are going to devise plans to shut them down, and we need to make sure that we’re firing on all cylinders,” Tar Heels coach Anson Dorrance said. “With single-game elimination tournaments (coming up), we need to be sure if they shut down Dunn and Ohai, that we’ve got other options.”

Next up is the ACC Tournament. UNC (16-3, 10-3), which will be the No. 3 seed, will host a quarterfinal game against Boston College Sunday at 1 p.m. No. 7 Duke (8-7-4, 5-5-3) will travel to Florida State.

h will be the No. 2 or No. 3 seed, will host a quarterfinal game against either Duke or Boston College Sunday at 1 p.m. No. 7 Duke (8-7-4, 5-5-3) will travel to either UNC or Florida State.

The Blue Devils entered Thursday on a five-game unbeaten streak, but were outshot 19-2 as UNC goalies Anna Sieloff (first half) and Bryane Heaberlin (second half) combined to post the shutout.

UNC improved to 36-2-1 all-time in the series. Despite the lopsided record, the rivalry had actually been tightly contested at Fetzer recently — the last six meetings had been decided by one goal or tied, including a Duke win in 2005. But there was nothing close about Thursday night’s game, as UNC had a 16-1 edge in shots in the first half.

“I would have bet everything that we have that we were ready to play tonight,” Duke coach Robbie Church said. “Give Carolina a lot of credit. They came out and they intimidated us.”

Still, the Blue Devils held the Tar Heels off the board for 36 minutes before Castleberry finally broke through.

Hanna Gardner threw the ball in to Kelly McFarlane, who headed the ball into the box. Castleberry, a freshman, received the flick and shot into the upper right corner for her first career goal.

“It’s crazy,” Castleberry said. “It’s so many things. It’s Halloween, it’s against Duke — our biggest rival — the emotions are incredible.”

It was UNC’s first goal off a throw-in since its fourth game of the season, against New Mexico.

The Tar Heels added a second goal 1:31 into the second half, when Elby slotted a low shot into the left side of the net. It was the first goal since August 2012 for Elby, who is still working her way back from an MCL injury and was focused on going low to counter Duke’s 6-2 keeper, Meghan Thomas.

Duke finally got its only shot on goal with 29:10 remaining when Laura Weinberg forced Heaberlin to drop to the ground for a save. The Tar Heels then added a third goal with 18:50 to play when 2012 National Player of the Year Crystal Dunn was fouled in the box, and Green converted the penalty.

Church said that senior Kim DeCesare did a good job marking Dunn, and the Duke defense held Ohai to one shot on goal. But UNC’s depth eventually made the difference.

“The first-line players press you and press you, and their depth is so good,” Church said. “They bring in a fresh player, and you’re off just a step or two.”