Reigning all-India junior champion Viraj, 15, made short work of Abel Tam from Malaysia 7 & 6 while Shubhankar stopped Arshad Ali 4 & 3 in the other semifinal.
All square at the end of two holes, Viraj got to being 4-up by the ninth and closed the match on 12th holes itself for a 7 & 6 victory.
His strokeplay round for 12 holes of regulation play was 2-under but with the bogeyman haunting Tam, it unfortunately turned to being a one-sided match.
Viraj is now one match away from being the youngest national champion in the history of Indian golf and in with a chance of holding both the senior and junior titles at the same time.
In the other match, between Shubhankar and Arshad, there were eight birdies that the players shared in what was a much closer duel than the score suggests.
Faldo Series India leg winner Shubhankar, 16, sounded the warning with birdies on the first two holes and while Arshad responded to get the score back to all square after four.
It became quickly a one-horse race as Shubhankar opened up a four-hole advantage at the end of 10 holes.
Minor slips in concentration saw the match get closer at the end of 13th when Arshad pulled back to 2-down but it was a case of too little too late as a birdie on the 15th from Shubhankar put the final nail in coffin.
Results (Semifinals): Shubhankar Sharma (3) bt Arshad Ali (10) 4 & 3; Viraj Madappa(5) bt Abel Tam (Malaysia, 8) 7 & 6.