Chowrasia charged into the early morning lead with a seven-under-par 65 while Lahiri, who had an afternoon start, enjoyed a flawless round that was highlighted by seven birdies at the Singha Park Khon Kaen Golf Club.
Asian Tour rookie Kalem Richardson of Australia posted a bogey-free 66 to share third place with Thailand's double South East Asia Games gold medallists Phiphatphong Naewsuk and Danthai Boonma at the USD 500,000 Asian Tour event.
Fresh off his victory at home, the 36-year-old also showed his fondness for playing in Asia again.
Starting on the back-nine 10th, he made a quick start with three birdies in his opening four holes.
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Chowrasia then raced further ahead with five more birdies in his next seven holes after the turn before a bogey on the closing ninth hole put the brakes on his charge.
"Indian players are doing very well this year and I'll try to win my first title abroad this week. My season has been very good. I did not play well at Q School in Europe but I'm doing well in Asia," said Chowrasia.