Sean Crocker fired a course-record 63 to lead by a single shot on the opening day of the Hero Open at Fairmont St Andrews.
The 25-year-old American picked up six shots in five holes on the front nine after going birdie-birdie-birdie-eagle-birdie from the 3rd.
And after dropping his only shot of the day at the 10th, he made four birdies in his next five holes to get to nine under par and stand alone at the top of the leaderboard.
After a day of low scoring, Frenchman Romain Langasque, English duo Ben Stow and Ashley Chesters, Swede Jens Dantorp and Spaniard Adrian Otaegui were in a tie for second on eight under, one ahead of the group containing home favourites David Law and Connor Syme.
Crocker opened his round with pars at the 1st and 2nd before picking up back-to-back birdies from close range on the 3rd and 4th.
He made it three in a row with a lengthy birdie putt from the fringe of the 5th green before firing an eagle at the 6th from 14 feet to jump to five under.
A birdie from nine feet followed on the 7th before Crocker carded his first bogey of the day at the 10th.
But he bounced back in style, reeling off birdies at the 11th and 12th to grab a share of the lead.
He sent his tee shot into the thick rough at the 13th but escaped with a par there before holing from 17 feet on the 14th to take the outright lead.
In a stunning up-and-down from an awkward spot in a bunker, the American made another birdie at the 15th before three closing pars rounded off a brilliant 63, which is Crocker’s lowest-ever round on the DP World Tour.
– Report from DP World Tour website