Lucas Bjerregaard fired the first hole-in-one of his career to take a one-shot lead after day one of the Open de France.
The Dane nailed his tee-shot at the par-three second on his way to a five-under 66 at Le Golf National, home of the 2018 Ryder Cup, putting him one clear of a four-way tie for second.
Thomas Pieters mixed five birdies with a sole blemish to become the first player to get to four under, while Thongchai Jaidee, Adrian Otaegui and defending champion Bernd Wiesberger were the pick of the afternoon starters.
Top seed Rory McIlroy sits five strokes back after ending an up-and-down day level par, as Masters champion Danny Willett struggled to a first-round 75.
Bjerregaard followed his slam dunk with a seven-iron from 202 yards with a birdie at the par-five next, before responding from a dropped shot at the fourth to post gains over the next two holes.
After missing a close-range birdie chance at the ninth to reach the turn in 32, Bjerregaard extended his lead by picking up strokes at the 10th and 14th.
A Bjerregaard blemish at the 16th allowed world No 1,051 Mathieu Decottignies-Lafon to briefly move alongside the Dane with back-to-back birdies from the 11th, only for the Frenchman to double-bogey the last to close a three-under 68.
Chris Hanson also briefly got to five under before posting a five at the par-three 16th to also end two off the pace, as Bjerregaard, completed his final two holes and set the clubhouse target.
"It was a great way to start my round," the 24-year-old told Sky Sports about his ace. "It's my first ever hole-in-one, so that was pretty sweet. I hit a great shot straight at it but we couldn't really see it.
"My clubs got lost on the way down here so Nike made me a new set yesterday. Maybe I should just keep these now and let the airline company keep my old ones."
Jaidee played his first three holes in three under and Wiesberger birdied three of his opening four on their way to matching 67s, while last-starter Otaegui closed a bogey-free day with a gain at the par-five ninth.
Andy Sullivan sits part of the group on two under, with recent Open qualifier Matthew Southgate alongside Nicolas Colsaerts a further stroke back.
Lee Westwood, Matt Fitzpatrick and Martin Kaymer all closed three over for the day, with Willett a further stroke back after double-bogeying the last.
Open qualification places are available for the four players in the top-12 and ties who have yet to book their place in the Royal Troon field, while double Ryder Cup points are also up for grabs this week.
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