*Note: All data is from the 1985 tournament to the present.
The 2017, as well as the 2016 iteration, almost saw a historical mark when three No. 6 seeds fell in the opening rounds of each tournament. If it weren’t for Notre Dame handling No. 11 Michigan in 2016, and then Cincinnati beating No. 11 Kansas State in 2017, these tournaments could have marked just the second (and/or third) time in the history of the NCAA tournament that all four No. 6 seeds fell to No. 11 seeds.
The first and only time that happened was in 1989, when Kansas, Georgia Tech, Alabama, and Oregon State all failed to make it past the round of 64. Aside from this outlier, the No. 6 teams have a fairly successful 85-51 record against the No. 11 seeds over the past 33 years.
That doesn’t mean the games aren’t exciting. The margin of victory is about three points per-game for the No. 6 seed, and about 60 percent of the 6-vs.-11 games have been decided by 10 points or fewer. The sixth-seeded teams also have swept the opening round just five times since the tournament moved to 64 team format (1987, 1992, 1997, 1999 and 2004). Over the past nine tournaments however, the scales are tipping toward the No. 11 seeds, who are 20-16 in that period.
In 2018, No. 6 and No. 11 seeds split the opening weekend. Miami was upset by Loyola Chicago — which went on to a historic run to the Final Four — and TCU was bested by Syracuse. While Houston and Florida both won their opening round games in 2018 as sixth seeds, neither advanced to the tournament's second weekend.
No. 6 seeds are 1-1 in the National Championship since the tournament expanded to 64 teams in 1985 with the Kansas Jayhawks winning in 1988. Kansas avoided upsets from No. 11 Xavier, No. 14 Murray State and No. 7 Vanderbilt in the first three rounds.
Speaking of Xavier, the Musketeers have been involved in the 6-vs.-11 opening round a grand total of nine times — five times as the No. 6 and four times as the No. 11. Xavier won its first game as the No. 11 seed in 2017, and has a 3-2 record as the sixth-seed. However, the game most associated with Xavier as the No. 6 seed is the double overtime thriller against No. 2 seed Kansas State in 2010 Sweet 16.