Syracuse beat the top 5 teams in the Big 12, in reverse order, on their way to the 2003 NCAA men's basketball championship.
4 of the 6 teams they played and beat in the NCAA tournament were Big 12 teams.
The schedule:
Regular season: beat Big 12 #5 Missouri, 76-69.
NCAA second round: beat Big 12 #4 Oklahoma State, 68-56.
NCAA Elite Eight: beat Big 12 #3 Oklahoma, 63-47.
NCAA Final Four: beat Big 12 #2 Texas, 95-84.
NCAA Finals: beat Big 12 #1 Kansas, 81-78.