Five time World Champion M C Mary Kom stormed into the semifinal round of the 12th Senior National Women Boxing Championships being played at Bhopal. She thrashed her opponent P Nirosha of Andhra Pradesh 17-0. Former World Champion L Sarita Devi of All India Police defeated also Vanlal Duati of Mizoram 26-12 in her quarter final bout today. Semi final bouts will be played tomorrow.