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 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.

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The three teams from the ACC as No. 1 seeds ties a record for one conference. "They earned their right to be there," said Stanford athletic director Bernard Muir, the chair of the selection committee.

Virginia gets a top seed for the second straight year, hoping to avoid another colossal embarrassment; the Cavaliers will face Gardner-Webb a year after becoming the first top seed to lose to a No. 16 since the bracket went to 64 teams in 1985.

The bracket, as always, included a few surprises and a few more debatable decisions from the selection committee that's been holed up at a Manhattan hotel this week, crunching the numbers.

Mid-major Belmont made it off the bubble, one of seven teams from non-power conferences to earn at-large bids. That was the highest number since 2015. Other bubble teams were Temple, Arizona and St. John's. Missing the tournament were Alabama, TCU and Indiana.

Michigan State made a strong bid for a No. 1 seed with its win Sunday over Michigan in the Big Ten title game. Instead, it was put on the "2" line, with a potential Elite Eight matchup against Duke in a tough East region.

Muir said Michigan State leapfrogged another No. 2 seed, Kentucky, by winning the Big Ten but "at the same token, we thought Michigan and Michigan State would both be on the '2' line."