In overtime, Redick, who finished with 36 points, gave Duke the lead for good at the 1:12 mark with a three-pointer from the right corner, pushing the Blue Devils ahead by a 94-91 advantage. Redick's free throw with 21 seconds remaining pushed the lead to four, but Florida State countered with a layup from Todd Galloway to trim the lead to 95-93 with 14 seconds left.
Florida State then failed to score on two straight possessions and Williams buried two free throws with three seconds on the clock to seal the win. Galloway tossed in a three-point basket as time expired to account for the final margin.
Duke led by two points twice in the final three minutes of regulation, but Florida State answered both times to send the game into overtime.
In posting his ninth 30-point game of the season, Redick made 12-of-25 field goals with three three-pointers while sinking 9-of-10 foul shots. He added six assists and six rebounds in 43 minutes of action. Williams was 8-of-14 from the floor and 11-of-16 from the line for 27 points. He also contributed 13 rebounds, four blocked shots and four steals.
For the Seminoles, Al Thornton had 37 points, 15 rebounds, five assists and three steals to lead the way. Jason Rich added 20 points and Alexander Johnson contributed a double-double with 13 points and 15 rebounds.
Duke travels to Chapel Hill on Tuesday night to face North Carolina at 9 p.m.