Shamim signed off with a rock-solid one-under 71 in round four of the Rs. 30 lakh PGTI event to finish with a tournament total of 13-under 275.
Kolkata's Shankar Das, who finished runner-up at eight-under 280 after returning an ordinary four-over 76 on Saturday, went past Rashid Khan to emerge leader in the Rolex Rankings.
Shamim (69-69-66-71), the overnight joint leader along with Shankar Das, had a slow start to the day as he bogeyed the first after pulling his tee shot into the rough.
Shamim then produced an exceptional chip to help himself to a tap-in birdie on the seventh. His bogey on the ninth didn't derail his efforts as he came back with a chip-in, his second of the week, for birdie on the 10th. He all but sealed the title with another brilliant chip on the 14th that led to a birdie.
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As a result of his win, Shamim has now climbed from 22nd place to 15th position in the Rolex Rankings.
Bangalorean C Muniyappa's final round 71 helped him claim third place at seven-under-281.
Sri Lankan N Thangaraja bagged fourth place at six-under-282 while Mohammad Sanju of Kolkata was a further shot back in fifth position.