The opening day of the NCAA tournament was spectacular, so it's saying something about how great Friday was that Day 2 eclipsed its predecessor in terms of exciting moments.

Here's what we learned from the jam-packed day.

1: Anything can happen

You go into March Madness expecting the unexpected, but even then, a few things that happened Friday were truly stunning.

First, Middle Tennessee State took down Michigan State.

The Spartans were rolling heading into the Big Dance and were the second most popular pick to win the whole thing by Capital One Bracket Challenge users.

Yet, Michigan State never led in its first-round matchup against 15-seeded Middle Tennessee State. Not even for a second. The Blue Raiders jumped out to a 15-2 lead, and despite Michigan State giving them its best shot, they held on and pulled off one of the biggest upsets in tournament history.

Michigan State wasn’t even the only top team to go down on Friday. 14-seeded Stephen F. Austin beat 3-seeded West Virginia, and 13-seeded Hawaii beat 4-seeded California.

Absolutely no one is safe in this tournament, and that’s what makes it so fun.

And who on earth could have predicted the crazy ending to Northern Iowa-Texas late Friday night? The Longhorns tied the game up with just a few seconds left, only for the Panthers to knock home a half-court buzzer beater to win the game.

What a day.

2: Sometimes the popular upset picks are the right ones

Coming into the tournament, Yale, Hawaii and Stephen F. Austin were among the most popular upset picks.

According to data from the Capital One Bracket Challenge game, the Bulldogs were the most-selected 12 seed to advance, the Rainbow Warriors were the most-selected 13 seed to advance and the Lumberjacks were – you guessed it – the most-selected 14 seed to advance.  

Well, Bracket Challenge users seem to know what they’re doing, as Yale took care of business on Thursday and Stephen F. Austin and Hawaii followed suit on Friday.

While you still have a Middle Tennessee State, who came out of nowhere to win (2.13 percent of users picked them), it’s clear that identifying Cinderellas is becoming easier.

3: Villanova is ready to go

Although a No. 2 seed, Villanova entered the 2016 tournament with plenty of doubters.

The Wildcats haven’t advanced past the Round of 32 since 2009 and suffered particularly tough losses as a No. 1 and No. 2 seed the past two seasons.

But Villanova is clearly making its mission to avoid another early letdown this year, because they came out firing on Friday.

Jay Wright’s squad put together one of the most dominating performances of its season and beat UNC Asheville 86-56. Simply put, everything went right for Villanova.

Villanova seemingly couldn't miss, shooting an impressive 56.9 percent from the field. Five players scored in double-figures, including Daniel Ochefu who rebounded from a tough showing in the Big East Tournament to post 17 points and 10 rebounds.

The Wildcats have proven this year that when they shoot well from 3 they’re nearly impossible to beat, and they showed that again on Friday. Villanova banged home 46.4 of its 3-point attempts, and UNC Asheville stood little chance.

Villanova was also extremely engaged on the defensive end, using high energy and pressure to fluster UNC Asheville. The Wildcats defense held UNC Asheville to 36.8 shooting from the field and forced 11 turnovers.

Villanova will face an Iowa team in the Round of 32 that has shown flashes of brilliance this season, but, given how they looked on Friday, the Wildcats seemed poised to get over the hump and return to the Sweet 16.

4: Sometimes an injury (or two) is the difference

Unfortunately, injuries are a part of the game, and their effect was certainly felt on Day 2 of the tournament.

Seventh-seeded Oregon State was without second-leading scorer Tres Tinkle and were taken down by VCU. Even more shorthanded, Cal was down leading scorer Tyrone Wallace and starter Jabari Bird (10.4 PPG, 40.9 3P%) and fell to 13-seeded Hawaii.

With the margin for error so slim in a tournament like this, injuries like these can make a huge difference. It was tough luck for both promising programs to be dealt such unlucky blows, but that’s just how it goes sometimes.

Keep an eye on health for the rest of the tournament, because it’s clear that even very talented teams sometimes can’t overcome injuries.

5: The ACC is making its case as the premier conference

Seven ACC teams made the NCAA tournament.

Six of them will be playing in the Round of 32. North Carolina, Virginia, Duke, Miami, Syracuse and Notre Dame all advanced, helping the ACC make a strong case it’s the top conference in the sport.

North Carolina and Virginia are legitimate championship contenders. Duke and Miami have Final Four potential. And while Syracuse is a 10 seed and Notre Dame is a 6 seed, they both have to be considered favorites to make the Sweet 16. The Orange will take on 15-seeded Middle Tennessee State, and Notre Dame will take on 14th-seeded Stephen F. Austin in the next round.

With the ACC possessing last year’s champion in Duke, this is shaping up to be back-to-back excellent tournaments for the conference.

Still, the ACC has plenty of work to do this year. The Big 12 still has a couple of heavy hitters standing in Oklahoma and Kansas that the ACC needs to outlast if it wants to truly wants to be known as college basketball’s top dog.