I've mentioned mgoblog.com a few times as my go to for Michigan news (in particular their fantastic coverage of Roy's famous "my coaching sucks" game). They also do a lot of good stuff when it comes to crunching the numbers from various analytics sites. A recent post did some digging using Bart Torvik's numbers and, in looking into how good Michigan's defense has been, also ended up showing how good Duke's is:

Here is a chart on which the best defensive teams in the country are to the top and the best at preventing threes are to the right. High major teams are the big bubbles; low majors are the little dots.



Michigan is sui generis amongst the best Ds in the country, more heavily dependent on their ability to prevent launches from deep than the other Ds that have poked their head above the fray. (For the record: those are Duke, Virginia, Texas Tech, Oklahoma, and the purple one way to the left is Kansas State.)
So essentially what this analysis is showing is that Duke is playing Top-5 level defense, but in a slightly different way than Michigan. Michigan is relying more on defending the 3 to yield their elite defense (which makes sense given the Wolverines have some incredible perimeter defenders in Zavier Simpson, Charles Matthews and Jordan Poole who aren't as stellar at the rim, but they can play aggressively on the perimeter because 7-foot-1 Jon Teske is in the paint), while Duke is relies more on defending the rim, which we know is the case based on our stellar block rate. That's not to say our 3 point defense isn't good, it certainly is (I'm pretty sure we're the next "top-right" most dot), but we're certainly not the outlier that Michigan is.

An interesting data point not only showing how good our D has been so far this year, but also how it's been that good, especially in comparison to some other teams.