Selva won the opening frame 29-22 before Khatri reeled off three consecutive wins convincingly with scores of 06-40, 09-34, 04-36.
With just one more frame needed for Khatri to win, Selva held his nerve and concentration to turn the tables, winning the final three frames 42-15, 40-20, 45-20.
Punit Sharma of Delhi had the day's highest break of 45 when he beat P Gangadhar of Andhra Pradesh 4-0 with scores of 46 (45)-07, 34-15, 27-17, 27-18.
Day Two and Round Two of the tournament will see the likes of Manan Chandra, Rupesh Shah, Shyam Jagtiani, I V Rajeev, Ishpreet Chadha, Neeraj Kumar, Asian Games Gold Medalist Rafath Habib, Abhimanyu Gandhi, Shahbaaz Khan, Shivam Arora, I H Manudev and West Bengal's state Champion in Billiards and Snooker Manish Jain in action.
In the men's section, 144 players divided into 12 groups will play double elimination as the last-4 players will join the last year's top-16 to make a total field of 64 players for the round-robin league.