BANGKOK, 16 Nov 2014 (AFP) - Khan's final-round 68 gave him a four-round 271 and 17 under for the event, a single shot ahead of Randhawa and overnight leader Thanyakon Khrongpha, who tied for second with 272.
The winner bagged three birdies on the back nine, making Jyoti and Thanyakon pay for dropped shots on 11.
The Thai, who started Sunday with a two-shot lead and was eyeing his first Asian Tour victory, regained his poise with a pair of back-to-back birdies on 13 and 14, to briefly threaten a late surge.
But his title challenge unravelled with another bogey on 16.
Fellow local star Kiradech Aphibarnrat, who started four shots off the lead, also threw himself into the equation with a solid 69, lit up by two birdies after the turn.
But the reigning Order of Merit champion could not notch any further birdies, leaving him still hunting a win this year after a sparkling 2013.
Both Khan and Randhawa, who had led the event at the halfway stage, also failed to bag birdies in the final few holes, instead slugging it out with pars to set up a nervy finish.
Teeing off last at 18, Khan kept calm to make a par five and secure the title at the Alpine Golf Resort.
The narrow defeat extends Randhawa's winless streak on the Asian Tour, which stretches back to the Thailand Open in 2009.
Leading scores after the fourth round at the par-72 Alpine Golf Resort course:
271 - Rashid Khan (IND) 68-69-66-68
272- Jyoti Randhawa (IND) 68-65-70-69, Thanyakon Khrongpha (THA) 69-65-67-71
274 - Kiradech Aphibarnrat (THA) 69-70-66-69
275 - Mithun Perera (SRI)70-70-67-68, Kalem Richardson (AUS) 71-69-64-71
277 - Jason Dufner (USA) 69-69-73-66, Danny Chia (MAS) 74-68-68-67, Jbe Kruger (RSA) 73-66-68-70, Scott Barr (AUS) 68-69-67-73