Lehigh became the sixth No. 15 seed to beat a No. 2 and the first since Norfolk State pulled off the trick earlier in the day.
Duke dropped its first tournament game for only the second time in the past 16 years, and this one occurred just 55 miles from its campus.
The Blue Devils had no answer for McCollum, a speedy guard who's a two-time Patriot League player of the year and the nation's fifth-leading scorer.
It didn't help that the Blue Devils hit just 6 of 26 shots from 3-point range.
Lehigh (27-7) led most of the game, drawing support from North Carolina fans who borrowed brown signs from Mountain Hawks supporters that read "Go Lehigh" to root against their rivals.
