(AP) - Clemson defensive coordinator Brent Venables has spent a lot of time watching No. 8 North Carolina score quickly. And he's sharing it with players in film sessions that get quite repetitive.
''It's 'How you like this play? How about this play? How about that score?''' Venables said Tuesday. ''First play of the Duke game, it's all jacked up, in-state rivalry, then they run the flea flicker. Touchdown, 80 yards.''
Venables knows the difficult challenge ahead for No. 1 Clemson (12-0) in slowing down the Tar Heels (11-1) in the ACC championship game Saturday night.
North Carolina is 16th nationally in yards gained at 495.7 a game. More impressive, in Venables' view, is how fast the Tar Heels can strike.
''There's a lot of explosive play-makers'' on UNC's offense, Venables said.
But Venables isn't without options; Clemson has a few play-makers on defense, too. Defensive end Shaq Lawson leads the country in tackles for loss. Linebacker B.J. Goodson and Ben Boulware have combined for 234 tackles, 22 of those behind the line of scrimmage.
No one at Clemson was completely sure how long it would take this year's defense to come together. The Tigers lost eight starters off last season's No. 1 ranked unit, including first-round NFL draft picks in end Vic Beasley and linebacker Stephone Anthony.
If that wasn't enough, linebacker Korrin Wiggins hurt his knee in camp and starting defensive tackle D.J. Reader took an extended leave of absence from the team for personal reasons in late August.
Despite all that, Clemson ended the regular season seventh in the FBS, allowing 288 yards a game.
''I thought we had a chance to be solid,'' Venables said. ''But probably not to the same level'' as 2014.
They'll need to approach it to corral the Tar Heels, who've scored 38 or more points in eight of their 12 games. They scored 66 points against the Blue Devils and had 59 a week later against Miami on the way to the ACC's Coastal Division crown.
Venables called North Carolina the best offense Clemson's faced all season, including Notre Dame and Florida State. If the Tigers don't bring their best effort, the perfect season and trip to the College Football Playoff could easily slip away.
''The margin for error is less because of the opponent,'' Venables said.
North Carolina coach Larry Fedora is equally awed by Clemson's defense.
''This is best football team we've have faced,'' he said. ''I mean, they're the No. 1 team in the country. And they've been that way for how many weeks? So they're really good.''
That defense, though, has gone through a late-season slide.
In the first seven games, only the Fighting Irish and Georgia Tech scored 20 or more points against the Tigers. Clemson has given up an average of 25 points in its past five contests.
Three-win South Carolina notched its highest point total of the season in a 37-32 loss to the Tigers last week - most of it coming after the Tigers had taken a 28-10 lead.
Lawson said the Tigers have been prepping for their league title game all season and will be ready to go at North Carolina.
The Tar Heels' worst offensive showing was their first game, an inexplicable 17-13 loss to the Gamecocks at the title game site, Bank of America Stadium.
''Ever since then they've been on fire,'' Lawson said.
But Clemson's defense has been practicing all season, Lawson said, against its own high-flying attack, which leads the ACC in total yards and can be as quick-strike as the Tar Heels.
''We're used to going against their offense because that's what our offense does against us when we're going to practice every week,'' he said. ''So it's not a big challenge for us. We've just got to be ready to play.''
A resurgent North Carolina defense adds to the challenge, though the Tar Heels have had a few hiccups in recent weeks. Some of those, however, can be chalked up to the team being in an unusual position: playing entire second halves against ACC opponents in what amounted to garbage time with the outcome long since decided by the Tar Heels' overwhelming starts.
UNC led 38-10 by halftime of the 66-31 win over the Blue Devils, was up 31-0 at halftime and 45-0 in the third quarter of the 59-21 victory over the Hurricanes and jumped to a 35-7 lead in the first quarter of Saturday's 45-34 win at North Carolina State.
The Tar Heels gave up 17.0 points per game through the first eight.
''I really do think we gave up too many points this past week, gave up too many yards,'' linebacker Shakeel Rashad said. ''And we have to go back and fix that. But at the same time, it's not like we're losing confidence over it, because everything that we're messing up is very fixable.''
North Carolina, however, will be without starting safety Sam Smiley for the rest of the season because of a torn left Achilles tendon. The school announced Thursday that Smiley had surgery to repair the injury suffered last weekend. The senior was tied for fifth on the team with 48 tackles.
Clemson has dominated the series of late, winning seven of the last nine and totaling 109 points in the past two meetings. The Tigers beat North Carolina 50-35 at home Sept. 27, 2014.