After a manic first weekend of March Madness 52 teams have left the “Big Dance” and the field of 68 has dwindled down to 16.

All four No. 1 seeds survived the first week of upsets and close finishes, but a few other favorites weren’t as lucky.

Big 12 tourney champs bounced in first round

The Big 12 tournament champions Missouri Tigers went from making a serious case for a No. 1 seed to not making it past the MEAC Champions. The 15th seeded Norfolk State Spartans became the fifth No. 15 seed to beat a No. 2 seed and the first since 2001, when another MEAC team (Hampton) also took down a Big 12 squad (Iowa State). That number grew to six that same night at the expense of college basketball powerhouse Duke.

Norfolk State center Kyle O’Quinn led the Spartans to an 86-84 victory over the 30-win Tigers with 26 points and 14 rebounds. “We messed up some brackets! We messed up some brackets!” yelled O’Quinn after the final buzzer. “We even messed up my bracket.”

After a decade of futility, a No. 15 seed triumphs not once but twice

Chances are O’Quinn’s bracket also didn’t have No.15 seed Lehigh knocking out No.2 Duke later that night. If those two results weren’t enough to leave brackets in shambles, the 13th seeded Ohio Bobcats ousted the Big Ten regular season co-champions Michigan Wolverines.

The round of 32 was relatively less chaotic as the Bobcats were only one of three double-digit seeded teams to win a second game and advance to the Sweet 16, joining 11th-seeded NC State and No. 10 seed Xavier.

No. 1 seeds have no trouble advancing to Sweet 16

The top-seeded Kentucky Wildcats eased by their first weekend and have garnered momentum as favorites despite earlier concerns based on their youth. With Duke out of the picture in the South region, the Wildcats have a relatively easy path to the Final Four in New Orleans.

Their toughest test could be a possible matchup against the No.3 seed Baylor Bears in the Elite Eight. Baylor won their first two games without a scare and Brady Heslip’s emergence as a 3-point threat adds yet another offensive weapon for the Big 12 battle-tested Bears.

The Syracuse Orange became a popular pick to be the first No. 1 seed to exit the tournament after center and Big East Defensive Player of the Year Fab Melo was ruled ineligible for the tourney. Jim Boehiem’s team just escaped a near-disaster loss to No.16 UNC-Ashville in their opener and pulled away from upset-minded Kansas State to punch their ticket to the Sweet 16.

Syracuse’s athletic style of play will be challenged by the Wisconsin Badgers, who play at a slower tempo. The Badgers’ playing style led them to an ugly victory over SEC Conference Tournament Champions Vanderbilt.

The Michigan State Spartans have displayed the same type of toughness and find themselves in a familiar spot. Draymond Green led Tom Izzo’s men past Saint Louis with 16 points and 13 rebounds.

“That was one of the tougher games we’ve played in,” said Izzo.”But you’ve got to give our guys credit, too. We didn’t pretend to be God’s gift to basketball. We know we’re a working man’s group. And we had to work today.”

Tom Izzo’s 10th trip to the Sweet 16 lands his Spartans in an intriguing matchup against Rick Pitino’s Louisville Cardinals.

The North Carolina Tar Heels powered their way to the Sweet 16 but lost their point guard in the process. Receiving a spark from the return of John Henson the Tar Heels seemed well on their way to another Final Four, but were handed a devastating blow when point guard Kendall Marshall broke his wrist. Having already lost his No. 2 ball handler Dexter Strickland in January, head coach Roy Williams must look to freshman Stilman White. Williams must find answers quickly with a potential matchup with the Big 12 Champions Kansas Jayhawks looming.