Is this not correct?
A No. 16 seed has defeated a No. 1 seed only
twice in the history of the men's NCAA tournament (since 1985), with top seeds holding a 162-2 record.
NCAA.com +2
2018: UMBC (University of Maryland, Baltimore County) defeated Virginia, 74-54, marking the first-ever 16-over-1 upset.
2023: FDU (Fairleigh Dickinson) defeated Purdue, 63-58.
NCAA