And then there were two.
Capping off what had already been an even more topsy-turvy weekend in college hoops than usual, the undefeated season of No. 2 Duke came to an end at the hands of unranked North Carolina State by a score of 87-75 on Sunday. The loss leaves just two undefeated teams left in the country.
For most of the game, Duke battled well. The Wolfpack shot the lights out from three-point range (10-of-16), but the Blue Devils got a hand in the face of those shots and responded well on the offensive end.
Until they didn't.
Contested three-pointers devolved into uncontested layups. Good defensive switches turned into miscommunications. During a stretch of eight minutes in the second half, Duke grabbed precisely one defensive rebound, and it was off a missed free throw.
That's almost impossible.
With 12 minutes remaining, NC State clinged to a 50-48 lead. Just a little more than six minutes later, the Wolfpack put the finishing touches on a 22-5 run to blow the game wide open.
It's one thing to go cold on offense. The Blue Devils certainly experienced plenty of that on Sunday. They shot 1-of-10 from the field over the final 9:45 of the first half, long before the aforementioned NC State run in which they only made one field goal.
During that stretch in the second half, though, Duke just completely gave up on both ends of the court. Mike Krzyzewski did his best Roy Williams impression by refusing to use one of his timeouts while the opponent built up an insurmountable lead, but his players failed to respond, seeming to only get more frustrated and disinterested.
NC State repeatedly got easy looks at the hoop, as Duke's help defense broke down over and over again.
Between a sense of urgency to force turnovers and a desire to simply stop the Wolfpack from draining threes, Duke's guards kept pushing further to the perimeter on defense. Unfortunately, Quinn Cook and Tyus Jones weren't quick enough to stay in front of Trevor Lacey or Cat Barber, and NC State was able to get into the paint with a head of steam just about whenever it wanted.
Unlike his cousin Emeka, Jahlil Okafor isn't wired to be an eraser in the defensive paint. He has blocked a respectable number of shots this season and even had three rejections on the day in Raleigh, but he spent too much time on the bench with silly fouls that made it even more difficult for him to do anything in those defensive situations.
On other possessions, Okafor's man, BeeJay Anya, received the ball in the paint and not a single Blue Devil came over to help on a big man who entered the game with a grand total of four assists on the season.
Worst of all were the tip-ins and putback dunks when Duke decided that boxing out was completely optional.
It was as if the Blue Devils just gave up hope when NC State refused to miss contested three-pointers. Duke decided not to waste energy on defensive possessions that were inevitably going to result in buckets anyway.
Throw in the fact that NC State's guards did a fantastic job of controlling the ball—the Wolfpack went nearly 23 minutes without a turnover—and the rout was on.
That lack of defensive effort was far too common last season, but Sunday was anything but the norm for this year's squad. The Blue Devils allowed NC State to score 1.24 points per possession despite holding each of their previous six opponents to 0.99 or less, according to KenPom.com (subscription required).
Red-hot shooting was to blame for the first 28 minutes, but Duke simply showed no heart when the Wolfpack started to run away with the game.
When asked what he thought coach Krzyzewski's message would be to his guys after the game, ESPN's Jay Bilas quipped, via ESPN.com: "I don't think he's going to be happy with the way their defense performed and the level of toughness and togetherness that they brought into the game."
Of perhaps equal concern was Duke's inability to get going on offense.
The Blue Devils entered the game as the most efficient offense in the country, according to KenPom.com, but they struggled to deal with Okafor being double-teamed every time he touched the ball. On several occasions, he received the ball on the low block and dribbled out to the perimeter to get away from the second man before facing the hoop and attacking the rest of the possession like a guard.
When Jabari Parker did that last season, it was no big deal. But it's hardly a good solution for Okafor to willingly take himself 22 feet away from the hoop when no one flashes to help him deal with a double-team.
As has been the case all season, though, Okafor still finished the day with favorite-for-Player of the Year numbers, tallying 23 points on just 11 field-goal attempts to go along with 12 rebounds.
Duke's bigger issue on offense was the polar opposite of NC State's strength on the day.
While the Wolfpack caught fire from three-point range before getting all kinds of open looks inside the arc, Duke struggled from downtown all day (7-of-27) and compounded the problem by driving into contested and off-balance shots in the paint.
According to Sports-Reference.com, Duke entered this game only once allowing an opponent to block more than four shots—a six-block game by Temple back in November. The Blue Devils had played three full games this season without having a single shot blocked.
On Sunday, the Wolfpack blocked 10 Duke shots.
Nothing fell on the perimeter, and absolutely nothing came easy in the paint. It's kind of a miracle Duke even scored 75 points in the game.
But cold-shooting nights will inevitably happen to the best of teams. Kentucky shot 28.1 percent from the field against Texas A&M on Saturday, but the Wildcats remained one of the nation's undefeated teams because of great defense.
Duke will shoot its way to a lot of wins this season, but the Blue Devils simply cannot afford another less-than-lackluster defensive effort like the one we saw against North Carolina State.
The Blue Devils looked exactly like what they are: a young team unaccustomed to playing true road games. Credit goes to NC State for playing a great game, but even more credit goes to the fans who treated the entire game like the final minutes of the national championship. It seemed to rattle the freshmen who had yet to experience that element of having "Duke" stitched on their chests.
Duke nearly gave one away earlier this week against Wake Forest too, but the Demon Deacons failed where the Wolfpack thrived, shooting just 15.4 percent from three-point range.
Okafor reflected on both ACC games, saying, "We should have lost at Wake Forest. NC State, they’re a better team than Wake Forest is, and they just capitalized on us not playing as tough. It was an unfortunate situation for us."
Prior to the start of ACC play, Duke's only true road game was the impressive win over Wisconsin, in which Tyus Jones led the way with 22 points. Where the heck was he on Sunday?
If the Blue Devils keep playing like this away from Cameron Indoor, Coach K won't be celebrating his 1,000th career win until February, as four of Duke's next six games are on the road against Louisville, St. John's, Notre Dame and Virginia.
There's still plenty of time before the NCAA tournament begins, but Duke better focus on defense if it wants to avoid an even more embarrassing loss than last year's fiasco against Mercer.
Kerry Miller covers college basketball for Bleacher Report. You can follow him on Twitter @kerrancejames.