GREENVILLE, S.C. — The Atlantic Coast Conference’s strong regular season only stood to set up a first-weekend flameout in the NCAA tournament.

The league had a record nine bids, but North Carolina – the No. 1 seed in the South – is the only one alive in the Sweet 16. And it was fortunate to survive a second-round game against Arkansas.

Top seeds Gonzaga, Kansas and UNC headline a regional round featuring 12 of the top 16 seeds, two more than last year.

The rest of the top conferences fared much better than the ACC. The Pac-12 is 8-1 and the Southeastern Conference is 7-2, joining the Big 12 (8-3) and Big Ten (8-4) with three Sweet 16 teams each.

Here’s a look at the updated Final Four paths for the top remaining teams:

SOUTH

This is the only bracket with the top four seeds still alive, so the Tar Heels’ path looks the same as on Selection Sunday.

UNC (29-7) needed a game-closing 12-0 run to rally past the eighth-seeded Razorbacks. Now the Tar Heels meet fourth-seeded Butler (25-8), which beat No. 1 seed Villanova twice this season.

That game is the undercard to Friday’s matchup of second-seeded Kentucky (31-5) and third-seeded UCLA (31-4) in Memphis, Tennessee. The Wildcats survived a tough game with Wichita State, and the Bruins beat Cincinnati to set up a rematch of a December game won by UCLA.

“I don’t know if all the other regions went chalk, but it’s 1, 2, 3, 4 in the South,” Bruins Coach Steve Alford said. “So that South Region and bracket is going to be a lot of fun.”

WEST

This is the only other region to have its No. 1 and No. 2 seeds make the Sweet 16.

Top-seeded Gonzaga (34-1) faces fourth-seeded West Virginia (28-8) on Thursday in San Jose, California; No. 2 seed Arizona (32-4) meets 11-seeded Xavier (23-13) — the lowest-seeded team still in the field after its rout of third-seeded Florida State.

If seeds hold, that would set up a rematch of a December game won by Gonzaga, 69-62. But Arizona didn’t have Allonzo Trier, who was suspended for the first 19 games for performance-enhancing drugs.

The matchup still would offer a Final Four breakthrough chance for the two coaches, Mark Few of Gonzaga or Sean Miller of Arizona, who have yet to get there despite a combined five Elite Eight appearances.

“I know this (team) certainly is right there, should be considered with any that’s ever played” at Gonzaga, Few said. “There’s probably two or three of them that should be in that mix. Ultimately we’re going to have to accomplish that Final Four to kind of put it to rest and all that.”

MIDWEST

The Midwest also had three of its top four seeds reach the Sweet 16. But it’s the bottom half of the bracket commanding the most attention with seventh-seeded Michigan, possibly the hottest team in the field.

The Wolverines (26-11) had a scary moment before the Big Ten tournament when the plane set to carry them to Washington slid off a runway during an aborted takeoff. They played the first game in practice jerseys but ended up winning the title, and now have beaten Oklahoma State and second-seeded Louisville for their first NCAA wins since 2014.

Michigan made 16 3-pointers against the Cowboys and hit 33 of 52 shots (63.4 percent) after halftime in those two wins.

“That’s been our identity in the last month and a half, finding different ways to win,” leading scorer Derrick Walton Jr. said. “Whether it’s the 3-ball or not, it’s finding multiple different ways to win.”

Michigan faces No. 3 seed Oregon (31-5) in Kansas City, Missouri, on Thursday. The Jayhawks (30-4) get fourth-seeded Purdue (27-7), the Big Ten regular-season champion.

EAST

Welcome to the lone topsy-turvy bracket after losses by No. 1 overall seed Villanova and No. 2 seed Duke.

Now third-seeded Baylor (27-7) is the highest remaining seed entering a matchup with seventh-seeded South Carolina (24-10), which is in the Sweet 16 for the first time after hanging 65 second-half points on the preseason No. 1-ranked Blue Devils in Sunday’s 88-81 upset.

The other half of Friday’s bracket in New York features fourth-seeded Florida (26-8) against No. 8 seed Wisconsin (27-9), which upset the reigning champion Wildcats on Saturday. The Badgers are in the Sweet 16 for the sixth time in seven years behind Bronson Koenig and Nigel Hayes – two holdovers from a run to the national title game in 2015.

“You have all types of your ranking systems, statistic, analytics guys that they put,” Hayes said. “The thing is with all those algorithms, they can’t calculate heart, will to win, toughness, desire. They can’t put that into a formula to come out with a percentage chance to win, and that’s the things that we have.”