Thokchom Nanao Singh assured himself of a medal by advancing to semi-finals while Olympic bronze medal winner Vijender Singh pulled off a stunning triumph over Uzbek Atoev Abbos to enter the quarter-finals of the Asian Boxing Championships in Zhuhai, China, on Tuesday. Youth World champion Nanao Singh (48kg) rallied to beat Chia-Lun Lu of Chinese Taipei 8-4 and reach the semi-finals.