Duke improved to 10-0, the fourth time in five seasons the Blue Devils have captured their opening 10 contests.
Redick made all 14 of his free throws and was the only Duke player to reach double figures.
Princeton (8-5) was led by Will Venable with 21 points.
A 17-2 run by Duke in the first half gave the Blue Devils a 29-12 lead late in the period.
Celebrity Couples of 2014 [PHOTOS]