Tyrrell Hatton fired a 66 over the Old Course at St Andrews to take the clubhouse lead on day three and put himself in prime position to win a third consecutive Alfred Dunhill Links Championship.
The Englishman became the first player to successfully defend this title last season and is now looking to become the first to win the same regular European Tour event three years in a row since Ernie Els at Heineken Classic between 2002 and 2004.
He opened up a three-shot lead at the turn but saw that cut into by fellow Ryder Cup hero Tommy Fleetwood, who was seven under for his round through 14 holes also playing the Old Course.
Hatton was 14 under with Fleetwood a shot back, two clear of 2004 champion Stephen Gallacher - who had completed his round at the Home of Golf - Dane Lucas Bjerregaard and Italian Andrea Pavan.
Australian Marcus Fraser, American Brooks Koepka, Italian Edoardo Molinari and South African Brandon Stone were then all out on the course five shots off the lead.
Hatton birdied the second to join the overnight leaders and when he eagled the par five fifth he was two ahead of the pack.
Pavan - playing at the Championship Course Carnoustie - birdied the fourth to cut the gap to one but Hatton was relentless and he got on the green at the par four ninth and made his eagle putt to turn in 31 and lead by three.
Fleetwood was fairly relentless himself as he started with three birdies and he made another from five feet at the fifth to move into a share of second.
Hatton made a bogey at the 12th and when Fleetwood holed a monster putt on the eighth, the lead was swiftly cut to one.
A Pavan bogey on the sixth dropped him to nine under and that was soon four off the lead as Hatton bounced back from his disappointment on the 12th.
The 26 year old put an approach at the 13th to five feet and holed a long putt on the next to move back three ahead.
Fleetwood would not be shaken off, however, and he holed from 15 feet on the tenth and then played a wonderful chip on the 12th to sit one back.
The leading duo were threatening to pull away but Pavan took advantage of the par five 12th with an eagle to get to 11 under and keep some pressure on.
Gallacher had been quietly going about his business, making birdies on the tenth, 12th and 16th to turn in 33. He made further gains on the sixth and seventh and when he drove the ninth and got down in two for birdie, he held the clubhouse lead.
That was just two back when Hatton missed the green on the 17th and failed to get up and down but he drove the last for a closing birdie to get to 14 under.
Pavan had three holes to play and Berregaard had four left at Carnoustie as he looked to mount a strong fightback.
The 27 year old double-bogeyed the sixth and turned in 37 but a hat-trick of gains from the 12th got him to two under for the day.