*Note: All data is from the 1985 tournament to the present.
The 1997 No. 4 seed Arizona Wildcats became the first team in the 64-team 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 beat South Alabama, 65-57 and start its championship run.
The number of upsets by No. 13 seeds over No. 4 seeds had been decreasing. Through 2017, the No. 4 seed had an .803 winning percentage. From 2014 to 2017, just one No. 4 fell in the opening round, with Cal losing to Hawaii by 11 points in 2016.
However, three No. 13 seeds have won in the first round in the last two NCAA tournaments. No. 13 UC Irvine upset No. 4 seed Kansas State 70-64 in the 2019 NCAA tournament.
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. Gonzaga and Auburn narrowly won their first round games, each taking four-point victories. Auburn lost its next game, losing to Clemson in the second round.
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.