Mexican filmmaker Alejandro G. Inarritu won the Oscar for best director for Birdman , his darkly satirical take on show business.
This was the first Academy Award for Inarritu, 51, whose film stars Michael Keaton as a washed-up, former superhero actor trying to make an improbable comeback with his own Broadway play.
"I am very, very thankful, grateful, humbly honoured by the Academy for this incredible recognition," Inarritu said. "This is crazy."
He praised his fellow best director nominees, saying "our work will only be judged by time."
Inarritu's best director win makes it two years in a row that the honour has gone to a Mexican filmmaker. His friend, Alfonso Cuaron, won the Oscar last year for Gravity , the 3-D space thriller starring Sandra Bullock and George Clooney.
Inarritu had faced stiff competition for the best director category from fellow filmmaker Richard Linklater and his coming-of-age tale Boyhood , which was filmed over 12 years using the same cast.
Previous feature films by Inarritu, Amores perros (2000), 21 Grams (2003), Babel (2006), and Biutiful (2010), have all received Oscar nominations in various categories.