Like every red-blooded American, Steven Izzo filled out a bracket in advance of the NCAA tournament. Tom Izzo, who coaches Michigan State, noted that his 13-year-old son had left part of the Midwest Regional blank.

“I said, ‘You haven’t finished this one,’” Tom Izzo said Thursday. “He said, ‘I’m having trouble with a game.’ I said, ‘What game?’ He said, ‘I’ve got you getting to Duke.’ I said, ‘That’s good. Where are we going from there?’”

Said Steven Izzo: “I don’t know, Dad. I don’t know.”

Izzo the Elder: “I tried to be a real parent — you know, not push your kid. Help him make intelligent decisions. I said, ‘Steven, I love you, man. Do it with your head, not your heart. Don’t worry about Mom or Dad.’”

The upshot: “The damn kid didn’t. He didn’t worry about us at all. He picked Duke.”

Possible ramification: “He’s a skinny little guy who won’t be eating for a month if we lose this game. That’s the way it works.”

As noted, Duke and Michigan State will meet Friday night in the Midwest Regional semifinals. Said Duke coach Mike Krzyzewski, who has taken four national championships, the first and the last in this city: “This is a big-time game. We’re excited to be a part of it. We want to be in big-time games.”

But this game, as Steven Izzo might not have known and Mike Krzyzewski didn’t care to learn, also represents the nation’s best program at its most vulnerable. Since 1999, Duke has lost seven times in the Round of 16, each time to a powerful team from a power conference. Six of those times Duke has been the higher seed, as it is this time.

Krzyzewski: “Thanks for making me worry.”

Most of those games tracked the same path: The free-flowing Devils smacked into an opponent that could override finesse with heft, and suddenly the stuff that worked in the ACC worked no longer. Think of Indiana outfighting one of Krzyzewski’s best assemblages in 2002. Think of Michigan State — Steve Izzo was then 5 — hammering the Duke of J.J. Redick and Shelden Williams in 2005. Think of the LSU of Big Baby and Tyrus Thomas soaring above and beyond the Devils in the Georgia Dome the next year.

As convenient as it is to see this game as Krzyzewski vs. Izzo, the cold truth is that it’s Duke’s players against Michigan State’s. Nobody ever outcoaches Krzyzewski, but sometimes his team isn’t as good as it’s cracked up to be. The Round of 16 is where lesser bands of Devils tend to get exposed.

As Mason Plumlee, Duke’s best player, said of the Spartans: “They’re one of the most athletic teams we’ve played.”

Krzyzewski: “They rebound better than anyone in the country.”

Technically, Michigan State ranks only eighth in the nation in rebounding margin. (It did, however, lead the Big Ten, the league of the big shoulders.) Duke ranks 208th, having been outrebounded on the season. Should this turn into a heave-and-tug affair such as the Devils-Spartans meeting of 2005, Michigan State will win.

But this could be one time when Duke actually is undervalued. The Devils are 20-1 with Ryan Kelly healthy, which the forward with the touch of a shooting guard is again. (When you’re making your shots, rebounding is of less importance.)

As for Michigan State: It’s good, but not nearly great. It was 2-5 against the three other Big Ten teams — Ohio State, Indiana and Michigan — still dancing as of Thursday afternoon. (It also lost to Miami, which won the ACC and split with Duke.)

It would be no great upset if the Spartans win. They are the No. 3 seed, and if Duke is the nation’s best program, Michigan State could well be second-best. Izzo has taken teams to six Final Fours and the 2000 national title. As Rick Pitino, who coaches top-seeded Louisville and who has an NCAA championship of his own, said of Krzyzewski and Izzo: “I have so much respect for both guys because of their longevity of excellence.”

And here we return to Steven Izzo, who sees rather a lot of his dad’s team and who nonetheless picked against it. The young man might well be onto something, and he might also have secured his future, at least as regards higher education.

Said Krzyzewski, smiling: “By the way, Tom’s son is going to be sitting on our bench (Friday night), and he’s got a scholarship to Duke. He might have sold (his dad) out, but he sold out for the right reason.”