BOSTON (AP) — Sitting at his locker packing his duffel bag slowly after the game, North Carolina guard P.J. Hairston paused, looked up and said a couple of words that simplified what looked like a very scary moment.

"Yeah, just a bad headache," Hairston said when asked if he was OK after he crashed to the court in the first half, banging his head before leaving on a stretcher in the Tar Heels' 82-70 win over Boston College on Tuesday night.

Before he was injured, though, Hairston was around long enough to ignite a first-half run and score 14 points.

"When P.J.'s making shots we're such a better team and all of a sudden he was hurt," guard Marcus Paige said. "That was hard."

Hairston hit the back of his head on the floor after colliding with teammate Dexter Strickland. A North Carolina spokesman said he suffered a concussion.

Before he went back to pack his last few things, Hairston was outside the locker room, fully dressed, but without his shoes on, listening to medical advice from a doctor.

"I saw him before the second half. He was woozy," North Carolina coach Roy Williams said. "He's feeling a little better now."

The Tar Heels led 48-33 at halftime and never let BC make a run in the second half.

"I said, 'One of your guys is back on the trainers' table,'" Williams said. "That's an old cliche and it's coach talk, but I believe it's true. Everybody's got to step up and play a little bit better than they did in the first half. We did talk about that old corny stuff."

James Michael McAdoo led North Carolina (14-6, 4-3 Atlantic Coast Conference) with 17 points and 10 boards. Strickland added 14 points.

Olivier Hanlan scored 22 points, Ryan Anderson 16 and Patrick Heckmann 12 for the Eagles (9-11, 1-6).

Boston College, which was 7 for 20 on 3-point attempts, lost its fifth straight game.

"It wasn't a great intelligent game necessarily in terms of decision making on both sides of the ball," BC coach Steve Donahue said. "On offense we just didn't have a real good flow to the game. We didn't turn it over, we got decent looks but when we needed them we didn't make them."

North Carolina, which entered its sixth straight week out of The AP Top 25 after spending 33 consecutive weeks ranked, opened a double-digit lead midway into the first half and coasted to the win despite losing Hairston.

The scary moment came with 4:02 left in the half when Hairston collided with Strickland as they were contesting a shot by Heckmann. After colliding with his teammate while they were both in the air, Hairston fell backward to the floor and hit his head.

"It was my fault," Strickland said. "I felt my elbow hit his face."

Hairston connected on all four 3-point attempts and hit two free throws before he was injured.

"He gave us a big boost off the bench, knocking down his 3s," Reggie Bullock said.

Hairston was on the floor for a lengthy time being attended by the medical staff — with Williams at his side. After he was helped to his feet, he attempted to slowly walk to the locker room — with each arm draped over a teammate — but he appeared to become woozy and was helped to the floor where he sat until paramedics brought a stretcher.

Surrounded by medical personnel, he was carted down a long hallway past the North Carolina locker room and into a medical room in the building, where he was expected to stay for the rest of the game. He left to an ovation, with a few players from BC standing at midcourt and applauding.

North Carolina, which led by 15 at halftime, kept BC from making a charge by getting timely transition baskets early in the second half.

"(Coach) just basically just told us everybody's got to pull together," Bullock said. "We've got to pull together and get this big-time win on the road."

When BC looked like it might rally, Marcus Paige and Bullock hit 3s that helped maintain a comfortable lead.

Heckmann's three-point play had cut it to 67-56, but Bullock followed with a trey from the left wing with 7 minutes left.

The Tar Heels, ranked as high as No. 9 in the nation in November, opened the game with sloppy play. Their shooting didn't help either as they missed six of their first seven shots until Hairston entered the game and sparked a 16-2 run over a 3-minute stretch by hitting three from beyond the arc.

BC jumped to a 10-5 edge before Hairston's 3 from the right wing ignited the run. After a 3-pointer by Bullock and a short jumper in the lane by Desmond Hubert, Hairston nailed a 3 from the top of the key. Brice Johnson then sank a baseline jumper before Hairston hit another trey, making it 21-12 with 1:30 left in the opening half.

During the spurt, Carolina went 6 for 6 from the floor.

The Tar Heels maintained their double-digit lead for the remainder of the half — thanks in part to three straight baskets by Jackson Simmons — and led 48-33 at intermission.

Behind Hairston's success from long range, the Tar Heels were 5 of 8 from 3-point range in the first half. They also shot 52.9 percent overall (18 of 34) and outrebounded the smaller Eagles 18-10.

The Tar Heels play their next two games at home, hosting Virginia Tech Saturday and Wake Forest on Tuesday.

BC next hosts Clemson on Saturday.