CRANS-MONTANA, September 5, 2013 (AFP) - Ranked 178 in the world coming into the prestigious EPGA event in the Swiss Alps, the 26-year-old from Bangalore built his score around two eagles, including a 140-yard second shot on the ninth that flew straight into the cup.
Spanish veteran Miguel Angel Jimenez - who set the course record of 61 on his way to winning here in 2010 - and Englishmen Paul Casey and Tommy Fleetwood are all two shots back.
"It's nice to come back here with a bang as it was a tough pill to swallow last year missing the cut in the manner I did, so I'm delighted," said Lahiri.
"I did not get off to a great start today (Thursday) to be one over after four but then you never really expect to then have two eagles, so I tried just to build on the momentum of that."
Two-time Ryder Cup winner Thomas Bjoern of Denmark is alone on five-under 66 after firing five birdies during a solid bogey-free round that puts him in early contention
Six players, including Spanish veteran Jose Maria Olazabal, Scotland's Stephen Gallagher and Thailand's Pariva Junhasavasdikul are a further shot back on 67.
The day, however, belonged to Lahiri, who was lying in fourth place after an opening-round 66 last year but got caught out by a change in weather conditions on day two and ended up shooting an 81 to miss the cut.
"Playing here last year was a new experience for me as I went out in the second morning with about four layers on and after three to four holes I was sweating like a pig," he recalled.
"The next thing I knew I had to peel off some clothes but then the clouds rolled in and the wind got up and I started then feeling like an icicle on the back nine.
"So that was a harsh lesson to learn and hopefully I can make amends this week." added Lahiri, who only qualified for his first major at the 2012 British Open, where he not only made the cut but scored a hole-in-one during his third round.
Leading first round scores on Thursday at the EPGA European Masters (GBR or IRL unless noted, par-71):
63 - Anirban Lahiri (IND)
65 - Tommy Fleetwood, Miguel Angel Jimenez (ESP), Paul Casey
66 - Thomas Bjoern (DEN)
67 - Richard Finch, Stephen Gallacher, Michael Hoey, Jose Maria Olazabal (ESP), Pariya Junhasavasdikul (THA), Barry Henson (USA)
68 - Mark Tullo (CHI), Jaco Van Zyl (RSA), Gaganjeet Bhullar (IND), Jeev Milkha Singh (IND), Brett Rumford (AUS), David Drysdale, Thongchai Jaidee (THA), Thomas Levet (FRA), Hao-tong LI (CHN), Eduardo De la Riva (ESP), Brooks Koepka (USA), Paul Lawrie, Alessandro Tadini (ITA), Victor Dubuisson (FRA), Gregory Havret (FRA), Maximilian Kieffer (GER)
69 - Scott Barr (AUS), Marcus Fraser (AUS), Richard Sterne (RSA), Gregory Bourdy (FRA), Alejandro Canizares (ESP), Andrew Dodt (AUS), Keith Horne (RSA), Stephen Dodd, Jonathan Moore (USA), Robert Coles, Rikard Karlberg (SWE), Matthew Nixon, Darren Clarke, Francesco Molinari (ITA), Danny Willett, Scott Hend (AUS), Darren Fichardt (RSA), Soren Hansen (DEN)