Cincinnati held a 22-point lead at one point in the second half and then went ice cold from the field, going on a field goal drought that would last 4 minutes, 51 seconds. It was the second-biggest comeback in tournament history, behind BYU's comeback from a 25-point deficit against Iona in the 2012 First Four.
The Bearcats' loss means none of the top four seeds in the South Region will advance to the Sweet 16, the first time that has happened since seeding began in 1979, according to ESPN Stats & Information.
As a result, No. 5 seed Kentucky won't face an opponent seeded higher than seventh in the South. According to ESPN Stats & Information, the last school to reach the Final Four without facing a top-six seed was Kansas in 2008.
"We got the deer-in-the-headlights look," Cincinnati coach Mick Cronin said. "The ball stopped dropping for us. We got fouled a lot of times, and it wasn't called around the rim. And that got in our heads."
Nevada guard Caleb Martin hit a 3-pointer with 54.1 seconds to tie the score, and then Josh Hall hit the go-ahead jumper with 9 seconds left. It was the first time the Bearcats trailed in the game and capped a stretch of 10:50 that saw them make just 3 of 19 field goals while Nevada made 13-of-19.
According to ESPN Stats & Information, Nevada had a 0.1 percent chance to win when it trailed by 22. Sunday's win came on the heels of a 14-point comeback against No. 10 seed Texas in the first round, in which the Wolf Pack's probability of winning was just 8.7 percent.
With Nevada's win, there have been five game winners in the opening weekend of the tournament, one shy of the most since the tournament expanded in 1985, according to ESPN Stats & Information.
When the game ended, a raucous celebration ensued. At one point, Nevada coach Eric Musselman jumped on a table at press row in front of a section of the school's fans.
In the locker room, Musselman took off his white dress shirt to celebrate.
"Coach works out every morning, so his shirt comes off a lot," said Martin, who had 10 points and five rebounds.
Said Musselman of the scene in the locker room: "I've never seen anything like it in my life. It's the happiest I've ever seen. It's the happiest I've ever been in my life. I couldn't be more proud of a team. Every single player in there, I mean, this feeling's never going away the rest of any of our lives."
With North Carolina's loss to Texas A&M earlier in the day, only two of the 2-seeds in the tournament will advance to the Sweet 16, while four teams seeded seventh or lower have made the cut.
Nevada will play No. 11 Loyola-Chicago in Atlanta.