Kumar fought back from 1-2 behind for a 11-9 5-11 4-11 11-5 15-13 win in 57 minutes yesterday.
However, the other two Indians Velavan Senthilkumar (U-17) and Tushar Shahani (U-15) lost their respective quarter-finals matches to exit the prestigious tournament.
Kumar next faces second seed Omar El Atmas of Egypt.