Five take-aways from the Duke/Michigan State game.

One, Duke is really good. Good enough to beat rugged second-ranked Michigan State without its best player, freshman Marvin Bagley III, who went out early with an eye injury. If the Blue Devils can beat a top ten team without Bagley, they can beat anybody with him.

Two, even if you hate Grayson Allen, he is one great player and shooter. Allen had a career-high 37 points against the Spartans, draining seven of 11 three-pointers, a couple of them when he was trying to get fouled more than make the shot. Allen is one of five Duke starters who will likely be in the NBA next year.

Three, the Blue Devils are the biggest team Mike Krzyzewski has ever had, using their impressive size to grab 20 offensive rebounds, not including Bagley’s five before he went out. Six-ten power forward Wendell Carter Jr. had a double-double with 12 points and 10 rebounds. Six-ten reserve Javin DeLaurier came off the bench to get seven rebounds, four assists and two steals.

Four, Allen credited many of his open looks to freshman point guard Trevon Duvall, who had a double-double of 10 assists and 17 points, adding six steals to help account for the Spartans’ 17 turnovers compared to only 9 for Duke. And Duvall didn’t shoot well, missing 13 of 20 from the floor, all four of his three-pointers and 4 of his 7 free throws.

Five, Duke was smart, playing zone for most of the game, effective enough to force Michigan State to hoist up 25 three-pointers, making 9. The Blue Devils aren’t a zone team, but these athletic freshmen and Allen played it well enough to make Sparty abandon its game plan of pounding it inside.

Duke retains its No. 1 ranking, deservedly so. It will lose when Allen isn’t as hot and someone can bang with them on the boards. But without Bagley for most of the game and Gary Trent, Jr. shooting poorly from close in and three-point land, there is plenty of fire power on this team.

Krzyzewski likes the one-and-dones because they are good enough to keep Duke high in the rankings all season, and that helps attract the next class of super frosh, which he has already secured for next year. And, although he knows that a group of one-year players has to gel extraordinarily well to catch lightening in a bottle and win it all, this group could do it.