Karunuday easily got the better of compatriot Nedunchezhiyan 6-3 6-3 in the quarter-finals.
In another last eight match, top seed Balaji came from behind to beat Japan's Bumpei Sao 1-6 6-3 6-3.
Third seed Vijayant Malik also registered his place in the last four round, beating a lethargic Garvit Batra in straight sets 6-0 6-3, while Prajnesh Gunnerswaran defeated Toshihide Matsui of Japan 7-5 7-6(3) to complete the semi-final line-up.