The most heart-breaking NCAA tournament bracket upsets, according to the data

One of the many, many reasons fans love the NCAA tournament is the thrill of the upset. Every year, double-digit seeds stun presumed favorites and high seeds fall earlier than expected. It's called March Madness for a reason.

Since 2014, when we have complete Bracket Challenge Game data, some upsets remain the most shocking. We went through the brackets and found the least-picked upsets that actually happened — and then ranked them by how many people (somehow) correctly foresaw the stunners. We kept it to first-round upsets, as this made it easier to compare games across the years thanks to the bracket format.

6. No. 14 Georgia State 57, No. 3 Baylor 56 in 2015 (9.21 percent had this one right)

We won't ever forget the shot. Or, really, the fall off the seat.

R.J. Hunter's 3-pointer with 2.7 seconds to play gave the 14-seeded Panthers a shocking win against Baylor — and caused his father, Georgia State coach Ron Hunter, to fall off his rolling chair in celebration.

Only 9.21 percent of BCG participants picked Georgia State to win, with No. 3 Baylor a popular pick to advance far in the bracket. Despite this unexpected result, another surprising 2014 upset proved to be even less likely, at least when going by BCG users. More on that soon.

5. No. 13 Buffalo 89, No. 4 Arizona 68 in 2018 (6.24 percent)

Wes Clark and the Bulls made it looks easy in the second half, even if only 6.24 percent of people had this on BCG brackets. Clark's 25 points helped Buffalo turn a two-point halftime lead into a comfortable 21-point romp — Arizona trailed by double digits for the final 10 minutes of the game.

Clark made 10 of his 14 shots for 25 points, with Jeremy Harris adding 23 points for Buffalo's first NCAA tournament win.

4. No. 14 UAB 60, No. 3 Iowa State 59 in 2015 (4.68 percent)

Here's that other 2015 stunner that stopped a Big 12 team. Though the Cyclones won the Big 12 tournament crown, the Blazers took out Iowa State in the first game. UAB shot only 34.8 percent, but the Blazers dominated the glass by outrebounding Iowa State 52 to 37.

3. No. 14 Mercer 78, No. 3 Duke 71 in 2014 (2.76 percent)

One year after Florida Gulf Coast busted brackets by making the Sweet 16 as a No. 15 seed, the Atlantic Sun provided another upset thanks to Mercer. The Bears defeated Duke by making 55.6 percent of their shots, with the Blue Devils struggling at 35.5 percent from the floor.

The next year, Duke regrouped and won the national championship. But in 2014, it was all about the Mercer Bears.

2. No. 16 UMBC 74, No. 1 Virginia 54 in 2018 (2.18 percent)

That's right. The historic, it's-never-happened-before upset of 16 over 1 is not the least-picked upset since 2014. Even still, only 2.18 percent of BCG players had UMBC making history against No. 1 overall seed Virginia.

Though Virginia played without injured star De'Andre Hunter, the Cavaliers came in 31-2. UMBC scored 53 points in the second half — almost matching Virginia's output for the entire game. The Retrievers made 12 of 24 3-point shots.

1. No. 15 Middle Tennessee 90, No. 2 Michigan State 81 in 2016 (2.13 percent)

Here it is. Only 2.13 percent of players had the Blue Raiders knocking out the Spartans. Michigan State came in 29-5, won the Big Ten tournament and had star Denzel Valentine. Add in coach Tom Izzo's seemingly annual March Madness runs — now up to eight Final Fours after a 2019 run — and MSU seemed like an obvious pick.

Instead, Middle Tennessee shot 55.9 percent from the floor to beat the Spartans, the eighth No. 15 seed to defeat a No. 2.

Here's the top-10 list of least-picked upsets: