You haven't seen a film about a girl boxer before, but what makes this one work so well as that star Michelle Rodriguez looks a sight more convincing in the ring than some 'real' female boxers.

A mixed-raced teen bored at school and skivvying at home since her mom died, Diana (Rodriguez) goes to the gym and channels her aggression into the ring, stealing money to pay for her tuition.

She proves more than a match for men and women and when the local authority sanctions bouts between the sexes, the scene is set for a ring showdown between Diana and her boxer boyfriend.

Director Karyn Kusama keeps her film tight, doesn't try to move it outside its range and gives a good idea of the dedication any fighter needs to succeed. With help from convincing action in the ring, her tale remains a contender throughout.