Gurgaon-based Jyoti Randhawa returned a five-under-67 to be on the leader's tail in second place.
In pursuit of his first-ever title at the RCGC, Lahiri made a perfect start to the tournament by registering eight birdies against two bogeys in round one.
Lahiri was in red hot form as he made birdie putts from 15 to 25 feet on the third, eighth and 17th holes.
The 26-year-old from the Eagleton Golf Resort, Bangalore, also hit it well by landing it within six feet for birdies on the ninth, 10th and 18th.
Lahiri's two bogeys came as a result of his ball being plugged in the bunker on the seventh and his tee shot landing in the water hazard on the 16th.
"I holed almost everything except for one short par putt on the 16th. The best shot of the day has to be the 25-foot downhill birdie putt on the 17th. That putt was not easy to execute. I struck it well and found most fairways. The conditions were tough in the morning as it was windy. I feel a lot more comfortable at RCGC now than I was few years back.
Randhawa had a flurry of birdies on the front-nine to make the turn at five-under.
He landed it within four feet on the first to pick up his first birdie.
