Aided by his caddie John Mulrooney, who was on the bag for Darren Clarke's Open Championship triumph last year, Bourdy defied driving rain at Crans-sur-Sierre, in the stunning Alpine resort of Crans Montana, to post a flawless eight under par round of 63.
That matched his previous best effort at the 2008 Estoril Open de Portugal, a tournament he went on to win, and the Frenchman is hoping the omens are good as he goes in search of his fourth European Tour title at this week's Ã¢Â‚Â¬2.1million tournament.
Bourdy said: "It was just a great day, I don't think I've ever played better. I played very well on the first day in Portrush, but that was right up there. This course isn't the most difficult, but it's not the easiest either because you have to hit the ball very straight, and I managed to do that today. I only missed one shot all day, but still managed to save par. My attitude was very good, I was very positive and that's why I finished very well."
Second place is shared by Sweden's Fredrik Andersson Hed and England's Oliver Fisher, who both notched seven birdies and a solitary bogey to sign for rounds of 65.
The leading Australian after day one is Scott Barr who has a start in the event courtesy of his Asian Tour status, this event being co-sanctioned between the European and Asian Tours. Barr recorded a round of 5 under 66.
Andrew Dodt had 67 and Marcus Fraser 68.
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