Looming at the top of this year’s March Madness bracket: Duke and its freshman force of nature, Zion Williamson.

The Blue Devils earned the top overall seed in the NCAA Tournament on Sunday, joining Virginia, North Carolina and Gonzaga as No. 1 seeds for the three-week hoops extravaganza that kicks off this week.

Williamson missed five games after wrenching his knee when his Nike sneaker blew out in a regular-season game last month. He's healthy again, playing well and not concerned about another potential injury that could impact his status as the likely top pick in the NBA draft later this year.

The Blue Devils are an early 9-4 favorite.

The Atlantic Coast Conference has a bit of history: For the first time the conference has three No. 1 seeds in the NCAA Tournament.

The ACC had league tournament champion Duke as the top overall seed. Virginia and North Carolina shared the conference’s regular-season championship and claimed No. 1 seeds as well.

That’s only the second time a league has managed three No. 1 seeds. The other time came in 2009 when the Big East had Louisville, Connecticut and Pittsburgh — though the Huskies were the only team to survive their bracket and reach the Final Four that year.

Virginia is the top seed in the South bracket, while UNC is on top in the Midwest.  The Georgia State Panthers are the No. 14 seed in the Midwest, facing third-seeded Houston Friday in Tulsa, Okla.

Gonzaga headlines the West Region after losing to Saint Mary’s in the West Coast Conference Tournament championship game. That was their first loss since falling to Tennessee and North Carolina in December.

The Zags have Big Ten runner-up Michigan as their No. 2 seed.

Belmont ended up on the right side of the bubble.

The Bruins earned their first at-large bid in program history and will face Temple in a First Four game in the East Region. Belmont is making its eighth tournament appearance, the last coming in 2015.

Belmont and Murray State shared the Ohio Valley Conference regular-season championship, but lost to the Racers in the conference tournament title game. Belmont was ranked 47th in the NET rankings and had a 2-2 record against Quadrant 1 teams.

The tournament starts Tuesday with a pair of play-in games, then gets going in full force Thursday.

The Final Four is set for April 6-8 in Minneapolis, where Duke is the early 9-4 favorite to win it all.