Mary Kom defeated Nikhat Zareen in the finals of the ongoing Women's Boxing Olympic trails in the 51-kg weight category here at the Indira Gandhi Stadium. The six-time world champion defeated Zareen 9-1 in the much-talked-about bout. In the 51kg category, Kom defeated her opponent Ritu Grewal in a unanimous decision while Zareen too outclassed her opponent Jyoti in a unanimous decision on Friday.