Undefeated won the Oscar for best documentary feature on Sunday,beating off strong competition in a wide-open field with no clear favourites. Directed by Daniel Lindsay and T.J. Martin,the film is an inspiring story about a struggling high school football team in a poor Memphis neighbourhood. But the film also courted controversy when martin uttered the word 'f*****g' in his acceptance speech in which he praised his fellow nominees - a rare Oscar night expletive. We would like to acknowledge our fellow nominees,they have inspired us. They have inspired us in so many ways,they should be up here with us,actually,that'd be f*****g amazing, Martin said. The word was bleeped out for the television audience,and minutes later Martin apologised to reporters backstage. First and foremost I'd actually like to apologise for this. I don't think it was the classiest thing. It did come from the heart. It was out of spontaneity,it was completely accidental, Martin said. Undefeated triumphed against Paradise Lost 3: Purgatory - the fight of three convicted murderers to clear their names,and Hell and Back Again - detailing the struggles of a war veteran returning to civilian life to win the Oscar statuette. The film has echoes of The Blind Side,the 2009 feature film in which a Memphis mother played by Sandra Bullock adopts a homeless black teenager and helps him achieve football stardom.