Gupta shot the tournament's best score of six-under-64 to make his way to the top, while Om Prakash Chouhan and Shankar Das returned scores of 66 and 68 respectively to end as the joint third round leaders at the scenic Shillong Golf Club.
Delhi's Honey Baisoya posted a 67 to be one off the lead in fourth place at five-under-205.
Gupta (71-69-64), lying overnight tied eighth, five off the lead, fought his way into contention with an error-free 64. Gupta, a winner on the PGTI earlier this year, picked up two early birdies on the first and fourth before accelerating with an eagle-birdie on the 10th and 11th thanks to two medium range putts from seven to 12 feet on the tricky greens.
Om Prakash Chouhan (69-69-66), fresh from his runner-up finish in Kolkata last week, too jumped into the fray on the third day courtesy a 66 that featured an eagle, four birdies and two bogeys.
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Chouhan, lying three off the lead in tied fourth at the halfway stage, was even-par through the front-nine in round three before striking it rich with three birdies and an eagle between the 10th and the 17th.
Chouhan looked good for the sole lead after his eagle-two on the 17th where he chipped-in from 40 yards. However, a three-putt for bogey on the 18th meant he had to settle for the joint lead.
Das closed the round on a high after sinking two crucial putts on the last two holes, the first a six-footer for birdie and the second from three feet for par.
Honey Baisoya was two-over till the turn but rallied with an eagle and three birdies on the back-nine for his 67. He would've also ended up sharing the third round lead had he not missed a short birdie putt on the 18th. Baisoya had to be content with fourth place going into the final day.