CHAPEL HILL, N.C. -- North Carolina hadn't struggled to score like this in quite a while. Boston College had an even tougher time on a final shot that would have delivered a memorable upset.
The 19th-ranked Tar Heels overcame their lowest-scoring game under Roy Williams and held off a late rally to beat the Eagles 48-46 on Saturday.
Tyler Zeller scored 16 points, and freshmen Kendall Marshall and Harrison Barnes had 10 points each for North Carolina (20-6, 10-2 ACC), which held Boston College to season lows of 26.9 percent shooting and 46 total points and won its third straight to reach the 20-win mark for the seventh straight season under Williams.
"Not a lot to say. We won. That's the bottom line," Williams said.
Joe Trapani and Reggie Jackson scored 13 points apiece for the Eagles (16-10, 6-6), who trailed by 15 but got back in the game by forcing turnovers on four straight possessions and pulled within two points on Jackson's 3-pointer with 1:10 left.
After Marshall missed on a drive with about 35 seconds left, Dallas Elmore rebounded and BC called timeout with 17.6 seconds remaining to set up its final play.
Jackson had the ball and looked to work it into the post, but nobody could shake free. So at about the 5-second mark, Jackson pulled up for a 3-pointer at the key over 6-foot-10 John Henson -- the ACC's leading shot-blocker, who had switched on a screen -- and it rimmed out.
"They did a good job of playing defense down low," Jackson said. "We wanted to post up but no one was open. I had the shot and I thought it was going down 100 percent, but it didn't."
Henson said Jackson's fingertips grazed his palm on the follow-through.
"Thank God for that, because it was that close," Henson said. "I thought it was going in for a second, too. ... Sometimes you get lucky, you know, because we have been unlucky in the past."
This one ended up much closer than the last meeting -- a 32-point North Carolina rout -- mainly because, for much of the way, BC got the slowdown game it desired.
Still, the Eagles were denied their first winning streak in a month by a Tar Heels defense that routinely worked them deep into the shot clock and held them to nine offensive rebounds while building a 44-30 rebounding advantage. Henson finished with 12 rebounds, nine on the defensive end.
The Eagles didn't score until nearly 8 minutes into the game, missed 13 of their first 14 shots in the second half and came up shy of their previous scoring low of 51 points against Florida State. They were held to their fewest points in an ACC game since joining the conference in 2005, and their fewest in any game since a 70-43 loss to Georgetown in 2002.
Jackson, the ACC's third-leading scorer, was 5 of 19 from the field. Trapani was 3 of 11.
"It was unbelievable how many shots went in and out," Trapani said. "We had a lot of good looks, but the shots just didn't go down."
With former player of the year Tyler Hansbrough watching from behind the scorers' table, the Tar Heels reeled off 13 straight points during a 15-1 spurt early in the second half that appeared to break the game open. After Marshall and Barnes hit pretty spinning layups down the lane, John Henson capped the run with a dunk that made it 39-24 with 11½ minutes left.
"One of the hardest things to do in basketball is to play with a lead," Marshall said. "At that time, it's hard to judge what's a good shot, what's a bad shot, working the clock, things like that."
That was the only thing that qualified as a run for a North Carolina team that entered with the ACC's second-most productive offense and was facing one of the league's worst defenses.
The Eagles allow an average of 71 points and teams shoot nearly 45 percent against them, but they held the Tar Heels to 36.8 percent and forced them into their lowest-scoring performance in both the history of the Dean Smith Center and in Williams' tenure in Chapel Hill. The previous low under Williams came in an 82-50 loss at Duke that ended the 2009-10 regular season.
"All we needed were a couple more shots to fall," Henson said, "and we would have blew the game open."
Points certainly were much tougher to come by than they were earlier this month, when North Carolina embarrassed the Eagles 106-74 in Boston. In the rematch, the Eagles were scoreless until Trapani hit a 3 more than 7½ minutes in.
The problem for North Carolina was it couldn't do anything at the other end of the floor.
The Tar Heels led 21-20 at the break, and both teams were held to first-half scoring lows. North Carolina's matched its single-half low during the Williams era, a mark first established last season at Georgia Tech.