March Madness has reasserted itself. The NCAA tournament came in like a lion and doesn’t show signs of ever being a lamb.

Those once-pristine brackets are now a continuously exploding minefield.

On Thursday, there were four overtime games — one that carried over until the early hours of Friday — a buzzer beater and bracket-busters all day. Some considered it the wildest, greatest and most exciting 13 hours in tournament history.

Mercer, making its first tournament appearance since 1985, followed the trend Friday by upending Duke and clearly outplayed the Blue Devils.

To survey the damage early on the first weekend:

Dayton is "The" team left from Ohio after putting out "The" Ohio State. When you consider how the Flyers have played for two months, it was not that big of an upset.

Harvard beat Cincinnati. Brains also have brawn.

Oklahoma, which helped birth Boise State’s rise to football prowess, might have done the same in basketball for North Dakota State. By the way, the Bisons have been overlooked with all the talk about schools that played in both bowl games and made the NCAA field. North Dakota State is the three-time NCAA FCS champion, the equivalent of a BCS championship.

Top-seeded Florida got a scare for Albany.

Manhattan, coached by Rick Pitino’s former ball boy with the New York Knicks, had defending champion Louisiville on the ropes with four minutes left.

Has madness gone mad?

This is why the NCAA tournament is the greatest sports event.

Seeding means nothing other than highly subjective suggestions. Brackets are busted because folks tend to pay more attention to the names on the uniforms and tradition rather than matchups and what’s under the radar.

Why are there surprises everywhere with lower seeds? There’s a surprise at every turn. At every turn, on the six-game journey, a gremlin can pop out. The "radar" has a limited range. There are good teams and good players everywhere.

Everybody has talent. The stars at mid-major conferences have played against many of those players on "name" teams in summer programs and are not intimidated.

Success by lower-seeded teams breeds confidence in others. "If (fill in the blank) can do it, why can’t we?" If the underdog stays within striking distance, it often plays looser because it’s a free shot in a single-elimination tournament.

Many of the good mid-majors teams have juniors and seniors who are good college players. The high-profile programs with one-and-dones can suddenly turn into one-then-done. The teams with seasoned players often have better chemistry and better continuity in pressure situations. The best individuals don’t always translate into the best teams.

The 3-point shot is a great equalizer against the power teams. A shooter or two on a roll can quickly change the dynamics of a game, and teams can catch up quickly.

Few leads are safe. Now you see a high-rated team with less-experience lose its composure just as much as a lower seed if somebody makes a run.

Games are played on a neutral court and a non-partisan crowd usually gets behind the underdog.

Some of the best teams with the best players are not good free-throw shooting teams. A simple, fundamental thing like making free throws is another equalizer.

Matchups make a difference. For example, Mercer, with its size and experience, was a perfect foil for Duke, which lived and died with perimeter shooting.

Thus, a form chart is without form. Resumes mean nothing with head-to-head matchups.

And that’s what makes it alternately frustrating and fun, captivating in any case.

(Sports columnist David McCollum can be reached at 501-505-1235 or or follow him on twitter @dmaclcd)