In 1997, No. 4 seed Arizona became the first team in the 64, or 68, team NCAA tournament format to defeat three No. 1 seeds en route to winning the national championship. As tough as it was to defeat Kansas, North Carolina and Kentucky, the Wildcats’ first game of the tournament was no walk in the park either, thanks to No. 13 seed South Alabama. Arizona had to overcome a 10-point deficit before it eventually closed on a 22-4 run to win, 65-57 and start its championship run.
In the not-too-distant past, the number of upsets by No. 13 seeds over No. 4 seeds had been decreasing. Through 2017, No. 4 seeds had an .803 winning percentage. From 2014 to 2017, just one No. 4 seed fell in the opening round, with Cal losing to Hawaii by 11 points in 2016.
However, five No. 13 seeds have won in the first round in the last three NCAA tournaments.
Luck for No. 4 seeds turned sour in 2018, when two were knocked out in the first round, and just one — Gonzaga — made it to the tournament's second weekend. Arizona was stunned by Buffalo in the first round, losing by 21 points, and Marshall upset Wichita State by six points. Ohio and North Texas moved on to the second round in 2021, after upsetting Virginia and Purdue, respectively.
Louisville owns the most appearances as a No. 4 seed. The Cardinals maintain an 8-1 first-round record, with the lone loss in a 2011 thriller to Murray State. Two of Louisville's wins were by 19 points and 22 points but the rest were decided by single-digits, including a two-point win over UC Irvine in 2015.
*Note: All data is from the 1985 NCAA Tournament to the present.