A No. 1 seed and two No. 2s did not get past the first weekend. A band of Peacocks from Jersey City took down a blue blood to reach the Sweet 16. They will be joined by a team that won two games last season.

March Madness lived up to its billing in the opening rounds of the NCAA Tournament and turns the corner to the Sweet 16 this week. If history is any indication, we can expect some next-level madness as the bracket winds toward the Final Four in New Orleans.

Here’s a few things to watch as the tournament shifts to San Francisco, San Antonio, Chicago and Philadelphia for the regional rounds:

TOP SEEDS

Gonzaga (1 seed). The Zags needed a while to get going against Georgia State and had a stiff test against Memphis, but found a way to reach the Sweet 16 for the seventh straight season.

Arizona (1). These swashbuckling Wildcats have a flair for the dramatic and, as their coach has said, a razor-thin margin for error. But know this: Tommy Lloyd’s bunch is fun to watch when they get rolling.

Kansas (1). Another NCAA Tournament, another Sweet 16. That’s 32 now for the Jayhawks, who have the type of roster to keep it going.

Duke (2): The Blue Devils had to wrestle out a win against Michigan State to keep Coach K’s final run through the bracket going. They face another grinder against Mark Adams’ roughneck Red Raiders.

Villanova (2). Any team led by Jay Wright and Collin Gillespie is going to be a tough out.

UNDERDOGS

Saint Peter’s. The small Jesuit school in Jersey has quickly become America’s hoops crush. Taking down No. 2 seed Kentucky in the first round had something to do with it. So does being led by a back-up guard sporting a rad ‘stache.

Iowa State. Two wins last season to two opening NCAA Tournament wins. Two more and these scrappy Cyclones will play in the Final Four for the first time since ’44.

Miami. Jim Larrañaga’s scramble defense left the Hurricanes’ first two opponents feeling trapped. Now they’re one of three ACC teams left standing.

Providence. Ed Cooley’s crew is in the Sweet 16 for the first time in 25. They’ve left bruised and battered opponents in their wake.

Michigan. Usually hard to call the Wolverines an underdog, but they are an 11 seed that barely got into the bracket. The preseason projections of greatness are finally coming to fruition.

KEY PLAYERS

Drew Timme, Gonzaga. Footwork of a ballerina, knows all the angles, lives for the big moments. Great ‘stache, too.

Jaden Ivey, Purdue. Anticipation on his drives to the basket is like waiting for a rocket to burst in the air — his dunks are more like explosions.

Bennedict Mathurin, Arizona. Spring loaded and clutch. And don’t make him mad — TCU found that out the hard way.

Doug Edert, Saint Peters. Has turned into a March folk hero with that caterpillar under his lip and penchant for hitting big shots.

Ochai Agbaji, Kansas. Has a knack for making the biggest plays down the stretch.

MUST-SEE GAMES

Gonzaga vs. Arkansas, West Region, Thursday in San Francisco. The Zags wants to play fast. The Muss Bus will look to slow their roll.

North Carolina vs. UCLA, East Region, Friday in Philadelphia. Blue bloods facing off, an Elite Eight spot on the line? Yes, please.

Iowa State vs. Miami, Midwest Region, Friday in Chicago. One of these two defensive-minded upstarts is going to the Elite Eight. First one to 50 may get it.

Texas Tech vs. Duke, West Region, Thursday in San Francisco. The fate of Coach K’s farewell tour could be in the diabolical defensive hands of Red Raiders coach Mark Adams.

Arizona vs. Houston, South Region, Thursday in San Antonio. The Wildcats weren’t supposed to go this far in their first season under Tommy Lloyd. Neither were the Cougars after losing two starters to injury. Neither is going to give an inch now that they’re here.

THE ODDS

A few Sweet 16 odds, according to FanDuel Sportsbook:

Best bet to win the championship: Gonzaga plus-240, Kansas plus-500, Arizona plus-650.

Worst title odds: Saint Peter’s plus-35,000, Iowa State plus-10,000, Providence plus-7,500.

Biggest spread: Purdue minus-12.5 over Saint Peter’s.

Smallest spread: Duke minus-1 over Texas Tech.

HOW TO WATCH

The TV and streaming schedule is tantalizing, keep the remote handy:

Thursday, March 24: West Region semifinals in San Francisco on CBS, South in San Antonio on TBS.

Friday, March 25: East Region semifinals in Philadelphia on CBS, Midwest in Chicago on TBS.

Saturday, March 26: West and South regional finals on TBS.

Sunday, March 27: East and Midwest finals on CBS.

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More AP coverage of March Madness: https://apnews.com/hub/march-madness and https://apnews.com/hub/college-basketball and https://twitter.com/AP_Top25

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