Romain Langasque posted a course record-equalling 61 at the Old Course at St Andrews to lead by one shot after the first round of the Alfred Dunhill Links Championship, on a day when Rory McIlroy and Jonathan Caldwell both shot a 68.
Langasque recovered from an early bogey with two eagles and eight birdies to reach 11 under par and tie Ross Fisher's record at the historic venue.
The Frenchman said the achievement will live long in his memory.
"I'm so happy, the last three holes were really fun and I made long putts," he said.
"It's amazing. I didn't realise that I have the course record here now and I think it's something I will remember for the rest of my life."
Countryman Frederic Lacroix was Langasque's nearest challenger on 10 under after firing a spotless 62 over at Kingsbarns, with another Frenchman - Antoine Rozner - tied for third alongside Dane Niklas Norgaard Moller on nine under.
World number two McIlroy began the week with a 68 at Carnoustie, as Francesco Molinari on his return to the venue where he won the 2018 Open Championship. Caldwell claimed his round of 68 at the Kingsbarns course.
Padraig Harrington and Shane Lowry both started their tournament at Carnoustie with Harrington faring the better with a round of 69, while Lowry finished the day on -2 after his round of 70.
As well as topping the leaderboard, Langasque and partner Roy Ryu co-lead the team competition on 14 under par alongside Andrea Pavan and Kieran McManus.
Due to the weather forecast, Friday's second round will have a shotgun start at 8.30am on all three courses, with leader Langasque tackling Carnoustie on day two