Georgia State and University of Alabama, two teams selected as a 14-seed, knocked out two 3-seed teams in Baylor and Iowa State, respectively. UCLA, an 11-seed, also upset Southern Methodist University, a 6-seed.
Sales Huddle Group CEO Sam Caucci pointed out some other close calls, with 4-seed North Carolina squeaking by 13-seed Harvard, while 3-seed Notre Dame barely made it past 14-seed Northeastern University.
North Carolina and Notre Dame aren't scrub teams either, as both schools played in the Atlantic Coast Conference championship, with the latter prevailing as the winner.
Obviously, winning big games is paramount in the tournament, but for some of the smaller schools -- particularly Georgia State and UAB -- wins like this help put their teams and school on the map.
For a school like Kentucky, Duke or Michigan State, selling tickets isn't really a problem. But for the smaller school, some may have to give away tickets in order to keep their attendance up, Caucci explained.
With big upset wins for the underdog, it could help boost ticket sales for next season, as demand increases. This could turn ticket sales into a revenue stream that wasn't there before, he said.
It also helps to create additional jobs in some instances and big upsets can lead to additional licensing revenue and sponsorship opportunities, Caucci reasoned.
More broadly speaking, the advertising opportunities for networks is enormous during the tournament. Caucci says the revenue is roughly three times that of the Super Bowl, as the duration of the March Madness tournament is much longer.
The large number of games and the fact that those games are spread over a number of different networks also helps, he concluded.