They chased down a 233-run target in 61 overs to take early lead with six points in the four-team points table of the premium domestic red-ball tournament.
India D tried clawing back with quick wickets of Rajat Patidar (44), Aryan Juyal (47), Baba Indrajith (7), and Hrithik Shokeen (0) in a span of 12 overs on Day 3.
However, an unbeaten 42-run partnership between Abishek Porel (35), and Manav Suthar (19) sealed the deal for India C.
India D added 30 more runs to their overnight score of 206/8 to finish at 236 all-out and post a 233-run target for India C, who managed a four-run lead in the first innings before getting bundled out for 168. Axar Patel again chipped in with 28 off 59 after scoring 86 in the first innings.
India C set the tone of the run-chase as three of their top four batters scored 40-plus runs. Gaikwad (46), and his opening partner Sai Sudharsan (22) forged a 64-run opening stand.
Later, Patidar and Aryan Juyal stitched an 88-run partnership for the third wicket to take the match away from India D. Off-spinner Saransh Jain picked four wickets
The match witnessed India C left-arm spinner picking seven wickets for 49 runs in 19.1 overs. In total he picked eight wickets in the match. Also, Baba Indrajith scored crucial 72 runs for the winning team in the first innings.
For India, Shreyas Iyer and Devdutt Padikkal smashed a fifth each in the second innings. Pacer Harshit Rana picked four wickets for them in the first innings.
India C will next face India India B from September 12 at the same venue.
India D will take on India A in Bengaluru.