Byeong-hun An carded a bogey-free 61 to match the course record at The Renaissance Club and establish a two-shot lead after day one of the Genesis Scottish Open.
The South Korean carded nine birdies to set the early target ahead of Northern Ireland's Rory McIlroy and Belgian Thomas Detry, while American Davis Riley threatened his lead in the afternoon. Although he carded seven birdies in eight holes from the third, An would not be caught in the third Rolex Series event of the season.
Riley was also bogey-free to sit at seven under after a 63, a shot clear of Detry and McIlroy and two ahead of South Korea's K.H. Lee and German Yannik Paul.
An is no stranger to claiming big wins on the DP World Tour, having triumphed at the BMW PGA Championship in 2015 en route to finishing seventh in the Race to Dubai and winning the Sir Henry Cotton Rookie of the Year Award.
He also has a win on the European Challenge Tour and revealed he felt right at home in Europe and on links having played in eight Open Championships.
"It's great," he said. "I feel like I'm back home. This is the Tour where I started my professional career. It's been great coming back and playing links golf, definitely it's nice.
"I started on the Challenge Tour playing links courses and played The Open many times. I like links golf.
"It's different than the courses we play in the US. You just have to land it in different spots. I really like it and as long as the weather is nice, and I prefer warm weather, but a links course, I feel comfortable. It can get tricky hitting shots into (the wind) but I think I did well today."
An got up and down to birdie the par-five tenth and then rattled off four birdies in a row from the 13th. Brilliant iron play saw him make a hat-trick of gains from inside seven feet before he made another up-and-down birdie on a par five at the 16th.
He made a nine-footer on the second and a smart chip helped complete his set of par-five birdies on the next before he put an approach to six feet at the short par-four fifth and holed from 24 feet for a closing gain.
"It was nice, always, bogey-free nine under par," he said. "I couldn't play any better. I drove it well and hit it well and chipped it well and putted well. That's a clean scorecard.
"I hit a lot of shots close, a lot of wedges close. It's one of those days, every shot you hit just has a perfect number. Pitched right, exactly, and how the ball reacted on the greens, everything was perfect.
"Some of the putts I had were very straightforward putts that I think I left in a good spot."
Riley made a two-putt birdie on the third and then put on a masterclass with the short stick to make four more in a row from between five and 26 feet.
A tee-shot to seven feet on the difficult par-three ninth saw him turn in 29 and he added another birdie with a two-putt on then tenth before parring his way home.
Race to Dubai Rankings in Partnership with Rolex leader McIlroy made a two-putt birdie on the par-five tenth and then holed from around 20 feet on the 12th and 13th.
A 41-foot putt on the 15th was followed by an up-and-down birdie on the par-five next and, while McIlroy bogeyed the 17th and second, he eagled the par-five third with a 30-footer from off the green after a 360-yard drive and made the most of the short par-four fifth after leaving himself a flick in.
Detry made birdie from inside 12 feet on the tenth, 11th, 12th and 14th to get off to a lightning start and, while he dropped a shot on the 16th, he left himself a tap-in on the next.
Another bogey came on the fourth but smart approaches to the fifth and eighth were followed by another stunner on the ninth as he got to six under.
Lee was bogey-free in his 65, while Paul carded four birdies, an eagle and a bogey to sit a shot ahead of American duo Max Homa and Will Gordon, local favourite Ewen Ferguson, South African Oliver Bekker, Frenchman Julien Brun, England's Ross Fisher, South Korean Tom Kim and Swede David Lingmerth.
