Adding to Indian contingent's fine showing were Jeev Milkha Singh and Gaganjeet Bhullar, who returned three-under 68 each.
Both Jeev and Bhullar had four birdies and one bogey each and they were joined in the group by Thongchai Jaidee of Thailand, who had an eagle, two birdies and a bogey.
Himmat Rai (73) and Digvijay Singh (74) were unable to exploit the fine scoring conditions, while C Muniyappa had just begun his round and SSP Chowrasia and Shiv Kapur were yet to tee off.
Lahiri started on 10th and his run of three pars was disturbed with a bogey on 13th. An eagle on 14th gave him the impetus and then there was a birdie on 15th followed by another eagle on par-4 18th.
Also Read
Four birdies, on first, second, fourth and ninth completed a superb day for Lahiri.
He was two shots clear of 2010 winner Miguel Angel Jimenez and recent Johnnie Walker Championship winner Tommy Fleetwood and was three clear of 2011 Omega European Masters winner, Thomas Bjorn (66).