The Tar Heels (32-5) attacked the undersized Bobcats (29-8) early in the post in building a 26-11 lead. Ohio rallied when its 3-pointers started falling and pulled within 29-22 at halftime.
Walter Offutt (26 points) drilled five 3-pointers after the break to spur a 20-9 run and give the Bobcats their first lead of the game at 47-46. D.J. Cooper (10 points on 3-of-20 shooting) extended that lead to 57-53 with a pair of free throws with 3:49 to play. There were three lead changes and three ties after that point.
Reggie Bullock (17 points, 10 rebounds) connected on a 3-pointer with 40 seconds remaining to give UNC a 63-61 lead. Offhut tied the game 15 seconds later on a driving basket, but missed his foul shot. North Carolina ran an isolation play for Harrison Barnes (12 points) as time wound down, but he lost the ball as he pulled up just inside the left elbow.
Bullock opened the extra period with a 3-pointer and that proved to be all the Tar Heels needed. UNC outscored Ohio 10-2 in overtime as the Bobcats missed all six of their field goal attempts.
Tyler Zeller delivered the first 20-20 performance in North Carolina NCAA Tournament history with 20 points and a career-high 22 rebounds. John Henson added 14 points and 10 rebounds. Friday marked the first time UNC has had three players with double-doubles in the NCAA Tournament.
North Carolina shot 40.0 percent (26-of-65, 7-of-22 on 3's) while holding Ohio to 32.4 percent (23-of-71, 12-of-32 on 3's). UNC's plus-33 rebounding edge (63-30) is the school's largest in the NCAA Tournament by seven.
INSIDE THE GAME
Going Away from the Bigs
North Carolina's size advantage was glaring as the teams took the floor for the opening tip. UNC's frontline stands 6-8, 6-11, 7-0, compared to Ohio's 6-3, 6-7, 6-8. And the Tar Heels took advantage of that discrepancy for roughly 30 minutes.
With 8:06 remaining in regulation, the UNC trio of Zeller, Henson and James Michael McAdoo had combined for 33 points on 14-of-24 shooting. They would attempt just four total shots over the final 13:06.
"You've got to give Ohio a lot of credit," Zeller said. "They did a great job of packing it in and trying to make us shoot from the outside. We kind of fell into it a little bit, but you've got to give them credit for changing their game plan."
Barnes provided his perspective from the perimeter on why UNC stopped going inside.
"We started making some shots," Barnes said. "Reggie stepped up big. He started hitting threes. I made one or two, so we just made a few shots, I guess. Fell in love with the jump shot."
The Tar Heels ultimately got enough clutch shooting from Bullock and Barnes to persevere, but their willingness to accept what the smaller Bobcats wanted them to do is troubling.
Perimeter Defense Ups and Downs
The Bobcats missed 17 of their first 20 field goal attempts, including their first five 3-pointers, in digging a 15-point first-half hole. Ohio tried its luck inside with minimal success, but failed to convert on the few open looks from the perimeter. That is, until Nick Kellogg (14 points) drained a 3-ball with 8:13 left to cut UNC's lead to 12.
Over the next 21 minutes and 37 seconds, the Bobcats connected on 12-of-22 3-pointers, including a 7-of-9 stretch out of halftime.
"We knew they were going to shoot it," UNC head coach Roy Williams said. "We wanted to get out there and we didn't do as good a job as we wanted to. They kept helping instead of getting out and guarding the threes."
The Tar Heels tightened up after Offutt hit a 3-pointer with 6:36 remaining in regulation. The Bobcats missed their final six treys over the last 11:36 of play.
Surviving the Turnovers
If Tar Heel fans had been told on Thursday that White would churn out six assists in 32 minutes without committing a turnover, the Vegas sports books would have been overwhelmed with cash for UNC to cover its 10.5-point spread.
But the other seven Tar Heels that played on Friday committed at least two turnovers, led by Zeller (6) and Barnes (5). Ohio's 13 steals were a season-high for a UNC opponent.
While White was efficient in protecting the ball, there was a noticeable lack of cohesion on the offensive end of the floor without Marshall running the point.
"I know that I felt open a couple times, but it was something that Kendall's been able to make a spectacular pass to get it there, whereas Stilman and Justin Watts haven't played with me as long and don't necessarily see it," Zeller said. "So you got to just be able to adjust. And it is difficult, but at the same time, I think we can do much better than we did tonight."
The Tar Heels' 24 turnovers are the most in the NCAA Tournament since posting 26 against Loyola Marymount in 1988.
Where is Black Falcon?
North Carolina needed a complete game from Barnes on Friday night. What it got was a 3-of-16 shooting display (2-of-9 3-pointers), five turnovers and spotty defensive play.
The sophomore forward has showcased his ability to hit clutch shots throughout his career, and he did it again on Friday, knocking down a 3-pointer to tie the game with 3:22 left in regulation. And despite the aforementioned size discrepancy, Williams elected to go to Barnes for the game-winner at the end of regulation instead of pounding the ball inside to Zeller or Henson.
"He's 3-for-16, I think, and I'm the coach and I'm dumb enough to put the ball in the guy's hand at the end of regulation because I felt like he would make a play," Williams said.
To Barnes's credit, he told reporters that poor shooting nights never affect him.
"You can be 0-for-25, but if you hit a big three down the stretch, that's all that matters at the end of the day," Barnes said.
Except that it does matter. For North Carolina to have any chance against Kansas on Sunday, Barnes has to have a much better performance, one that Tar Heel fans will talk about for years to come. If he just counts on hitting one clutch shot, then that opportunity may never present itself.
Follow IC on Twitter @InsideCarolina.