The top three freshmen started the season sidelined by injuries -- and one of them still isn't right. The leading returning scorer has been banged-up, suspended and reduced to an internet meme. The Hall of Fame coach missed seven games because of back surgery. And folks have had a good time mocking Duke's struggles.

But now look.

The Blue Devils spent Thursday night beating North Carolina 86-78 inside a packed and wild Cameron Indoor Stadium and extending their winning streak to four games. They're now 19-5 overall, 15-2 with Mike Krzyzewski on the sideline and starting to take form as a true national title contender.

Yes, Duke is a true national title contender.

Only a fool would suggest otherwise.

Here are five takeaways from Duke's win over UNC:

1. Grayson Allen was terrific

An uncreative North Carolina fan, in advance of this rivalry game, published a video in which he dressed up as Allen and tripped people around campus. Then, presumably, that same uncreative North Carolina fan watched the CBS Sports Preseason National Player of the Year drop a game-high 25 points on the Tar Heels before fouling out with 62 seconds remaining. Allen made seven of Duke's 13 3-pointers in the win. He's 20-of-41 from beyond the arc in Duke's four-game winning streak. My calculator says that's 48.8 percent. "Feels great," Allen said in a televised interview. "There's nothing like winning at home in a big game."

2. Jayson Tatum started slow but finished strong

Duke scored 40 points in the first half. Tatum was responsible for none of them. But the heralded freshmen and projected top-10 pick of the 2017 NBA Draft got 19 of the Blue Devils' 46 second-half points and was exceptional, really, on both ends of the court. Also: He did this to North Carolina's Kennedy Meeks ...

3. It should be noted that UNC was shorthanded

I want to note this because North Carolina fans would if I didn't. So let the record show that Hicks didn't play because of a strained right hamstring suffered in Wednesday's practice. He's averaging 12.8 points and 5.6 rebounds, which means UNC played Duke close at Duke without its third-leading scorer and third-leading rebounder. If you're looking for a reason the Tar Heels might win the rematch on the final Saturday of the regular season, that's a good one.

4. Harry Giles is the freshmen who still isn't right

I mentioned that in the lede. I didn't write it to be mean. I just wrote it because it's true. The freshman forward who was, two summers ago, the consensus projected No. 1 pick of the 2017 NBA Draft only played 10 minutes against UNC, and that's because playing him more would've been bad for Duke. Right now, sad as it is to type, Giles is just a guy. Perhaps he'll be more than that later this month or next month. But, right now, he has little influence on what Duke is accomplishing.

5. Duke has the stuff to win a national title

I know a lot of you gave up on Duke thanks to a prisoner-of-the-moment mentality. But it's not too late to reconsider and recognize that a team with nine McDonald's All-Americans can win a championship.

This is not the Premier League.

Early struggles never prevent anybody from cutting nets.

To be a champion in this sport, all you have to do is make the NCAA Tournament and win six or seven games in it. Literally nothing that happens in November, December, January, February or even early March serves as an obstacle. So keep an eye on Duke, and here's why: No matter what happens between now and March, the Blue Devils will enter the NCAA Tournament with a great roster and the greatest coach.

That's a fabulous combination.

I wouldn't bet against it.