1. Villanova vs. Georgetown (1985)
This remains one of the biggest NCAA tournament upsets ever. On paper, Georgetown was the strongest team in the bracket. Firstly, they were the defending champions. Meanwhile, they also had Patrick Ewing on their books. The future NBA star performed brilliantly for them all season (via History).
They faced Villanova for the championship after beating twice already that year. Georgetown even led and outshot their rivals at several stages. But Villanova was clinical on the day. They defeated two first seeds and a pair of seconds seeds to win the title. It was one of the greatest wins in college basketball history.