Gary Boyd moved into the early lead at the Alstom Open de France as the Englishman turned in a four under par 32.
When Boyd had two tens in a round of 88 at the ISPS Handa Wales Open just over a month ago, he said: "I know my best golf is just around the corner."
And the 25 year old appeared to have found it at Le Golf National near Paris.
Boyd, twice a runner-up since graduating from The Challenge Tour at the end of the 2009 season, registered three birdies in the first four holes to be alongside Australian left-hander Richard Green, who had a hat-trick of birdies from the 14th after starting on the back nine.
Boyd then added another gain at the ninth to move one clear.
Northern Ireland's Graeme McDowell, runner up in last month's US Open, was level par after four, but World Number Three Lee Westwood bogeyed the 12th - his third - and playing partner Martin Kaymer, who beat him in a play-off for the title three years ago, double-bogeyed there after kicking off with a birdie.
Welshman Jamie Donaldson came back down to earth with a bump after his Irish Open victory. He took six at the 427 yard 13th and by dropping another shot on the 15th was already three over.
When Boyd added a further birdie at the tenth he was five under and two clear of the field.
New Zealand's former US Open Champion Michael Campbell had moved into joint second place thanks to birdies at the seventh, tenth and 11th.
Campbell, down to 910th in the Official World Golf Ranking, failed to qualify for The Open Championship at West Lancashire on Tuesday and has made the cut in only two of his last 15 European Tour events.
Alongside him on three under was Italian teenager Matteo Manassero, while Kaymer was level par, McDowell two over and both Westwood and Donaldson four over.
For Westwood that came as a result of a second bogey at the long 14th and then a double bogey on the next.
Boyd remained five under with four to play and had company when Manassero followed birdies at the first and long third with a 25 foot putt for another at the next.
Some of the bigger names continued to trail well behind, however. McDowell was still two over with seven to go, Kaymer was alongside him after bogeys at the 16th and 17th, while Westwood's birdie at the 16th did at least lift him back to three over.
Ryder Cup stars Justin Rose and Ian Poulter were among the later starters, as was Open Champion Darren Clarke.
