This is a different kind of one and done.

Instead of three weeks filled with upsets, small schools and all those other feel-good stories that make March Madness so special, basketball fans only get one this year.

Heading into the second week, the NCAA tournament is now a big boy’s game, dominated by a who’s who of major college programs.

All but two of the 16 teams in the regional semifinals will be from power conferences. The lone exceptions are Xavier, which is hardly a stranger to this time of year, and Ohio University, a big school with a small, but no longer unknown, basketball program.

According to STATS, this will be the first time since 2003 that 14 teams from the six major conferences have made the Sweet 16. Two of those conferences, the Big Ten and Big East, put four teams each into the round of 16.

“To play in the NCAA tournament is great,” said Kansas coach Bill Self, whose Jayhawks are one of two Big 12 teams left in the field. “But to feel the full benefit from an exposure standpoint for your program, you need to get to the second weekend.”

The Sweet 16 matchups:

—No. 1 Kentucky vs. No. 4 Indiana and No. 3 Baylor vs. No. 10 Xavier in the South; No. 1 Syracuse vs. No. 4 Wisconsin and No. 2 Ohio State vs. No. 6 Cincinnati in the East; No. 1 North Carolina vs. No. 13 Ohio and No. 2 Kansas vs. No. 11 North Carolina State in the Midwest; and No. 1 Michigan State vs. No. 4 Louisville and No. 3 Marquette vs. No. 7 Florida out West.

Those 14 power-conference teams have a combined 93 Final Four appearances and 33 national titles.

While two No. 2 seeds, Duke and Missouri, fell to 15s Lehigh and Norfolk State in a shocking second round Friday, all four No. 1s got through the first week safely — the first time that’s happened since 2009. A year before that, all four top-seeded teams made it to the Final Four for the only time.

It’s possible again this year, though Carolina will have to overcome an injury to a key player to get there.

The Tar Heels defeated Creighton 87-73, but point guard Kendall Marshall broke his right (non-shooting) wrist.

“You can ask any question you want, but I just told you all we know,” Tar Heels coach Roy Williams said when announcing the injury. “We do not know anything else.”

Though there are few truly small teams left in this year’s draw — such as the Butlers and VCUs and George Masons that have crashed the Final Four over the last decade — there will be three squads bringing double-digit seeds to the final 16.

The list starts with No. 11 North Carolina State, the program that pretty much set the standard for March Madness upsets and gave us one of the most memorable moments in college sports: Coach Jim Valvano running around the floor at The Pit, looking for someone to hug after Lorenzo Charles grabbed Dereck Whittenburg’s air ball and put it in at the buzzer for an upset over powerhouse Houston.

That was in 1983.

In 2012, the Wolfpack snuck in as one of the last at-large teams to make the field. On Sunday, they upset No. 3 Georgetown 66-63 to gain their Midwest Regional matchup against Kansas.

“We always talk about we have such great history at NC State, but it’s also time to build some new history,” coach Mark Gottfried said.

No. 10 Xavier comes from the Atlantic-10, the closest thing to a power conference without actually being one. This is the fourth Sweet 16 appearance in the last five years for the Musketeers, who made their biggest news this season with an ugly brawl against crosstown rival Cincinnati that led to suspensions and knocked the team out of whack.

“The only guys that know what we went through were the guys who were in the locker room,” coach Chris Mack said. “Some would say it’s self-inflicted, but I know we have great kids. And I’m really proud of them today.”

Then, of course, there’s No. 13 Ohio — enrollment 17,000 but with a basketball program that has, well, basically nothing in common with the state’s better-known behemoths who will join them in the Sweet 16 — Ohio State, Xavier and Cincy.

“I do think our guys have a chip on their shoulder,” Ohio coach John Groce said. “I think our guys look forward to playing on the big stage against quality competition.”