Kathryn Bigelow today became the first woman in history to win the best director award at the Oscars.
Her low-budget Iraq war film, The Hurt Locker, about a bomb disposal team, was the big winner at the ceremony. It took six academy awards, including those for best picture and best original screenplay.
The Hurt Locker triumphed the over the 3D blockbuster Avatar, directed by Bigelow's former husband, James Cameron.
Cameron, who sat behind Bigelow at the ceremony in the Kodak theatre in Hollywood, was one of the first to offer congratulations when he reached over to tap her on the shoulder.
Bigelow described the award as a "moment of a lifetime" and dedicated her Oscar to the servicemen and women in Iraq and Afghanistan. "May they come home safe," she said.
The Hurt Locker is an apolitical film focusing on the heroism of bomb disposal experts. It was critically acclaimed but not a box office success and was attacked as unrealistic by bomb experts.
Bigelow was only the fourth woman to be nominated for best director in the 82-year history of the Oscars.
The previous female nominees were Sofia Coppola for Lost in Translation in 2003, Jane Campion for The Piano in 1993, and Lina Wertmuller for Seven Beauties in 1975.
Barbra Streisand, the director of films including Yentl and The Prince of Tides, presented the award.
In interviews after the ceremony, Bigelow resisted reporters' attempts to encourage her to gloat about her victory over Cameron. "I think he is an extraordinary film-maker," she said.
Much of the build-up to the Oscars had focused on the rivalry between the former couple, who married in 1989 and divorced two years later.
It was the subject of jokes from the hosts of the ceremony, Steve Martin and Alec Baldwin.
"She was so pleased to be nominated with him she sent him a beautiful gift basket – with a timer," Baldwin said.
Bigelow has for decades been a female pioneer in the male-dominated world of action movies.
Her previous films include Point Break, Strange Days and K-19: The Widowmaker. "I'm drawn to provocative characters," she told the Guardian in video interview last year.
At the Directors Guild of America Awards, where she also won the top honour, Bigelow said: "I suppose I like to think of myself as a film-maker", rather than as a female film-maker.