Arun, who had staged a similar comeback in the pre-quarterfinals yesterday, made the most of the next exchanges in the business end of the match to win the 48-minute encounter 17-21 21-16 25-23.
Till that come back, Arun looked out of sorts after taking a medical break while trailing 15-19 in the decider but showed the tenacity and presence of mind to hang in and force his opponent to play a pattern that benefited him in the final analysis.
Arun will now face second seed and Shushant Chippalkati junior international champion Aditya Joshi of Air India who rallied from a disastrous first game to beat fourth seed Arsalan Naqvi of 11-21 21-12 21-16.
In the girls' section, defending junior national champion Ruthvika Shivani stayed on course for a double crown after reaching the under-17 and under-19 finals.
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In the u-17 semifinal, the Gopichand Academy trainee ended the dream run of Maharashtra qualifier Mrunmayi Saoji 21-7 21-13 and then came back to defeat second seed Reshma Karthik of Karnataka 21-9 21-13.
The u-19 girls will see Ruthvika taking on Rituparna Das, who defeated Maharashtra's Rasika Raje 21-12, 21-13.