Duke came back down to earth a bit on Sunday.

After looking utterly unbeatable through two preseason games against Belmont and Tennessee, the Blue Devils were tested against No. 17 Kansas in an exhibition game on Sunday at Allen Fieldhouse. Duke played a fantastic second half to win 90-83. Here are a few quick observations.

Joaquim Boumtje Boumtje's Defensive Versatility

Duke freshman Joaquim Boumtje Boumtje was tested on the offensive end much more than he has been in either of the Blue Devils' first two preseason contests. Kansas was physical and did a good job forcing the seven-footer to take difficult shots. Although he didn't make as much of an impact on the offensive end of the floor, his elite defensive versatility was on display.

Boumtje Boumtje spent time guarding Kansas' 6'8" 5-star freshman guard Tyran Stokes and Melvin Council on the ball, and he showed his ability to guard multiple positions at different parts of the floor. It wasn't perfect, and there will certainly be some sort of transition period for Boumtje Boumtje to fully adjust to the physicality of college basketball, but his ability to guard different players at different areas of the floor stood out.

Boumtje Boumtje is such a unique defensive tool for Jon Scheyer. It's not too often a head coach can put his seven-foot big man on an opponent's facilitator, but the rookie is a very unique prospect.

Patrick Ngongba's Improvements Offensively

This was the first time throughout the preseason that the Blue Devils were challenged on the interior and in physicality. Getting high-percentage looks inside was difficult, but Patrick Ngongba led the way for Duke with over 20 points.

Ngongba changed his frame this offseason and used his body and footwork to create space for himself to finish around the basket. Additionally, he matched the high level of physicality the Jayhawks presented. The junior big man also has a chance to be one of Duke's best passers this season, which was the area of the game he made the biggest jump in from his freshman to sophomore year.

Ngongba is a true anchor inside, but also has great vision to find cutters when the defense crowds him near the basket.

Getting Tested Early Is a Good Thing

Duke beat Belmont by 40 points in a scrimmage on Oct. 8, then took down No. 8 Tennessee by 39 points in an exhibition. It looked practically unbeatable throughout its first two preseason contests, but Duke came back down to Earth a bit in Lawrence.

Facing a great team on the road in a packed environment early is great adversity for a team, especially with new pieces, to handle. Scheyer and his staff learned about their team today, but the Blue Devils are still in a pretty fantastic spot, given it's still October.