Which No. 1 seed will be the NCAA Tournament's first big victim?

It’s the day after Selection Sunday, and all across the nation, brackets are being carefully constructed before inevitably getting busted when March Madness tips off Thursday.

Virginia, Villanova, Xavier, and Kansas enter the tournament at the top of their respective regions — the perfect position for a dramatic upset, a la Villanova getting knocked out by Wisconsin in the second round of last year’s tournament.

The fall of the No. 1 seeds is inevitable — a Final Four consisting of all four top contenders hasn’t happened since 2008, the year Steph Curry upset Georgetown. Somewhere along the way, someone is bound to stumble, making room for a sleeper to crack the upper ranks. Once play begins, it’s only a matter of time before one of these championship hopefuls takes a great fall.

This year, that team is Xavier.

No. 3 overall heading into March Madness, Xavier is a strong team from a school that consistently makes a decent postseason showing. Their place at the top of the West, however, may be misleading.

Although the Musketeers finished out their regular season first in the Big East (over fellow No. 1 Villanova) and with only four losses, weakness lurks, ready to emerge with the pressures of the postseason.

Two of Xavier’s regular season losses came thanks to Villanova, who ceded their spot at the top of their conference in exchange for the No. 2 spot in the nation, just ahead of the Musketeers. The others are less understandable: one against ASU, who will fight Syracuse for a spot in the tournament this Wednesday, and the final loss to Providence, who later knocked Xavier out of the Big East tournament early in one of the biggest conference tournament upsets this season.

Only three starters return from Xavier’s incredible 2017 run, where they made it to the regional finals from an 11-seed, only to fall to eventual runner-ups Gonzaga.

Assuming Xavier makes it past their bubble opponent in the first round and either Mizzou or FSU in the second, it would not be surprising to see them fall at the hands of the 4-seed Bulldogs yet again in the third round.

Xavier’s offense relies on explosive point-scoring, led by Trevon Bluiett’s almost 20 PPG, to intimidate their opponents. On the other end of the court, one of Gonzaga’s strengths, even after losing one-and-doner Zach Allen to the draft in 2017, is limiting their opponents’ scoring. Gonzaga has held their last three challengers to an average of 61 points, holding BYU to just 54 to secure the WCC title with a dominant 20-point win. And as last year showed, Gonzaga refuses to be overlooked.

Even if Xavier manages to pull off a win over the Bulldogs, sleeper UNC may be laying in wait to take them out in the Elite Eight. The West as a region is a particularly tough pool, with Michigan, UNC, Gonzaga, and Ohio State all poised to bust some brackets.

Virginia also faces a treacherous path to the Final Four, but as the team sitting unanimously on top of the coaches’ poll heading into the tournament, they’ve proven their toughness time and time again. Making it through the ACC, the toughest conference in college basketball, with a 17-1 record on the regular season, doesn’t just happen for any team.

If anyone’s primed to face the South, stacked with Arizona, Tennessee, and Cincinnati, it’s Virginia. In the East, Villanova prepares to face Purdue and possible upsetters West Virginia and Virginia Tech, the only teams that have managed to defeat UVA this season.

In the North, Kansas enjoys what’s arguably the easiest path to the Final Four, with Michigan State and an inconsistent Duke team that’s seen losses to Boston College and St. John’s.

But for all the speculating and stat-crunching for the world, who knows what will happen at tipoff.