Lahiri, who will get married next month, fought back from a double bogey on 13th as he leapfrogged from second to go past the clubhouse leader, Baek Seuk-Hyun of Korea (65), who finished at 16-under.
Lahiri (68) finished at 17-under after rounds of 70, 69, 64 and 68 and was one shot clear of Baek and Cameron Smith (70).
Lahiri, ranked 102 in World rankings at the start of the week should move inside top-75 when the rankings are released tomorrow. He is currently the top Indian in world rankings. He will also move to the top of the Asian Tour Order of Merit. It was Lahiri's fourth win and he has now won each year since 2011 and the only Indians with more Asian Tour wins than him are Jyoti Randhawa (8), Arjun Atwal (7), Jeev Milkha Singh (6) and Gaganjeet Bhullar (5).
Making it a great outing for Indian golf were SSP Chowrasia (68), who was in contention for a brief while before ending tied fifth at 14-under and Rashid Khan (71), who won his maiden Asian Tour title last month at SAIL-SBI Open, had a topsy-turvy day with five birdies and four bogeys and finished tied ninth at 13-under.
Rahil Gangjee (70) was tied 22nd and Arjun Atwal, who had one eagle on 18th and a birdie on sixth ended tied 39th.