Giant Killers' 10 most likely first-round upsets in March Madness bracket 2021

It's upset-picking time.

Whether you've been glued to conference play or just found out that there's an NCAA tournament this year, we're all searching for that 12-over-5 upset that's going to hit. And if you're anything like us, you want some numbers to point you in the right direction.

Giant Killers is here to help. Back for its 15th NCAA tournament, Giant Killers is our metric-based model that predicts the likelihood of upsets. You can read the details here, but the idea is fairly straightforward: Giant Killers takes the base probability of an upset from ESPN's College Basketball Power Index but adds a further wrinkle of incorporating the strengths, weaknesses and style of the two teams in each individual matchup.

As always, Giant Killers exclusively considers matchups with at least a 5-line seed differential (so, a No. 11 over a No. 6 in the first round, for example).

There are no sure things in the NCAA tournament, other than that there will be upsets -- and our model is here to try to identify them before they happen. Here are Giant Killers' top 10 most likely upsets of the first round.

No. 11 UCLA Bruins vs. No. 6 BYU Cougars
Upset chance: 41%

Mind you, the Bruins have to beat Michigan State in the First Four before they can even think about BYU. But if UCLA makes it this far, the GK model likes its chances against the Cougars.

Mick Cronin has shooters like Jaime Jaquez, Jules Bernard and David Singleton who are as accurate from beyond the arc as they are selective. Matt Haarms and BYU's very good interior D won't necessarily be a problem for Cronin's guys, who won't be fazed by the Cougars' rather methodical pace, either. UCLA is even more deliberate.

No. 11 Syracuse Orange vs. No. 6 San Diego State Aztecs
Upset chance: 39%

Jim Boeheim's team was considered a long shot to make the tournament for the better part of February and March, but now that Syracuse is here it might well take on the appearance of a Giant Killer. The model likes what it sees in the pairing between the Orange and San Diego State.

Notoriously weak on the defensive glass, Syracuse has drawn an opponent that is merely normal and not mighty on its own offensive boards. Conversely, the Aztecs really want to force you to commit turnovers, but one thing you can say about an inconsistent Orange team with a short bench is that it takes excellent care of the ball.

No. 14 Colgate Raiders vs. No. 3 Arkansas Razorbacks
Upset chance: 35%

This one should be fast, furious and high-scoring -- not the typical Giant Killers recipe for success. But Colgate's scoring ability from all over the court, and especially its advantage in efficiency from beyond the arc, give it a far better chance than most No. 14 seeds of pulling an upset.

It's tough to judge a team like the Raiders, who have played such a weak schedule, but that's why opponent adjustments are badly needed in any college basketball model. Giant Killers has that covered, and it still thinks Colgate's a real threat.

No. 12 Georgetown Hoyas vs. No. 5 Colorado Buffaloes
Upset chance: 28%

Is this just about Georgetown's Big East tournament run? Yes and no. There's no "momentum" factor in the Giant Killers model: It's judging these teams based on the entirety of their seasons, because every game is a valuable data point.

That being said, our opinion of Georgetown has (reasonably) changed of late. Over the past week, the Hoyas leapt up 23 spots in BPI's rankings, which make up the base of the Giant Killers model. That's what a blowout over Creighton will do for you. There's better than a 1-in-4 shot Patrick Ewing's squad keeps the run going over the Buffs.

No. 13 Liberty Flames vs. No. 4 Oklahoma State Cowboys
Upset chance: 26%

Liberty would have been a little better off if it could have matched up against a team that matched the Flames' slow pace, but it's still a dangerous first-round foe. Darius McGhee leads an efficient Flames attack that ranks in the top 10 in 2-point and 3-point field goal percentage, per KenPom. And Liberty takes care of the basketball, too.

This is a tough draw for the Cowboys.

No. 14 North Texas Mean Green vs. No. 3 Purdue Boilermakers
Upset chance: 25%

Giant Killers loves a slow-paced matchup, because Giant Killers loves variance. Purdue is a better team than North Texas, we can all agree. But because the Mean Green are the 21st-slowest team in the nation and the Boilermakers are 60th, Purdue will have fewer possessions to assert its dominance.

Purdue's advantage is on both ends of the court, but at least North Texas is the better 3-point shooting team -- something the model also likes to see.

No. 11 Michigan State Spartans vs. No. 6 BYU Cougars
Upset chance: 23%

Note that our GK model is a good deal less bullish on a pairing between MSU and BYU than it is when it's UCLA facing the Cougars. In part, that's due to the deficiencies of a Michigan State team that, prior to its late push, missed a high percentage of its shots and was only average, in Big Ten terms, at defending the paint.

Still, a 1-in-4 chance is something, and Tom Izzo has at least been getting made shots from Joey Hauser. Malik Hall has also looked impressive of late, and if nothing else the Spartans match up with a very good BYU team in terms of both size and depth.

No. 11 Utah State Aggies vs. No. 6 Texas Tech Red Raiders
Upset chance: 22%

Utah State might have an opportunity to pick up some extra possessions along the offensive glass: It ranks 16th in offensive rebound rate while the Red Raiders are 254th in defensive rebound rate, per KenPom.

If the Aggies can take advantage of that area of strength while simultaneously avoiding a matchup weakness -- turnovers -- then they'll have a shot in this matchup between two high-end defensive teams.

No. 12 UC Santa Barbara Gauchos vs. No. 5 Creighton Bluejays
Upset chance: 21%

Creighton looked completely out of sorts in losing to Georgetown by 25 in the Big East title game. Catching the Bluejays at the right time could present an opportunity for a would-be "Killer" that hits its 2s and takes very good care of the ball.

UCSB enters the bracket having won 18 of its past 19 thanks to efficient scoring from both sides of the arc by lead guard JaQuori McLaughlin. The model isn't as optimistic on this game as it is on some others higher on this list, but at a minimum McLaughlin will test the defensive prowess of the CU backcourt.

No. 11 Wichita State Shockers vs. No. 6 USC Trojans
Upset chance: 13%

While the GK model isn't seeing a lot to like in this pairing when USC has the ball (shorter version: Evan Mobley is outstanding), there's a chance Wichita State could get some things done on offense against the Trojans.

Tyson Etienne is an excellent high-volume perimeter scorer for the Shockers, and the one safe bet in advance is that Isaac Brown's team will get its fair share of shots at the basket. USC doesn't really force turnovers and, anyway, Wichita State doesn't often commit them.