Dito Montiel nabbed the coveted dramatic directing award for "A Guide to Recognizing Your Saints," which he adapted from his memoirs.
"This is really nuts, man," the surprised first-time helmer said in accepting the award. "I didn't make a list, and if I did name them we'd be here for eternity."
The film — whose producers include Sting and his wife, Trudie Styler — also received a special jury prize late Saturday for its ensemble cast.
"Saints" stars Robert Downey Jr. and Shia La Boeuf — who play Montiel at different ages — as well as Rosario Dawson, Chazz Palminteri, Dianne Wiest and Channing Tatum.
For the first time, both the grand jury prize — the festival's top honor — and the audience award went to the same film in both the dramatic and documentary competitions.