Defending champion Tyrrell Hatton produced a brilliant bogey-free 65 for the second consecutive day to surge into a five-shot lead after day three of the Alfred Dunhill Links Championship.
The Englishman entered round three in a share of the lead and when he made a sixth birdie of the day on the fourth at Kingsbarns he had a six-shot advantage and looked set for a commanding cushion heading into the final day.
Frenchman Grégory Bourdy produced four birdies in a row on the front nine at Carnoustie to cut the gap to four but a closing gain for Hatton moved him to 18 under and put him in a dominating position.
Bourdy signed for a 66 at next season's Open Championship venue to sit two shots ahead of last week's winner Paul Dunne, with former World Number One Luke Donald and last year's runner up Ross Fisher eight shots off the lead.
Hatton made his European Tour breakthrough at this event last year as part of a stunning run of form that catapulted him to 14th in the Official World Golf Ranking.
He then made just two cuts in nine events from the Masters Tournament to the US PGA Championship but has back-to-back top tens since and carried that recent form into his defence.
He made an excellent start with a birdie on the tenth and added further gains on the 12th and 14th before a stunning approach to the first moved him to 15 under. He did well to get up and down from a pot bunker for another birdie on the third and when a big drive left him with a flick into the fourth, the lead was up to six.
Bourdy had birdied the tenth, 14th and 16th before dropping a shot on the next but responded with those four birdies, highlighted by a monster putt on the sixth.
To win at the home of golf once is incredible but to do it again and defend would be a dream come true - Tyrrell Hatton
Hatton then played a deft chip into the par five ninth for a closing gain.
"Last year, this event was a fantastic moment for me," said Hatton. "It's great to be back and I'm enjoying my first defence.
"Last year was a new experience for me going out leading a tournament and I managed to do a really good job. Made myself very difficult to catch, hopefully I can do that again tomorrow.
"I'll certainly try my best to do that. That's all anyone can ever do is try their best and I'll certainly do that.
"To win at the home of golf once is incredible but to do it again and defend would be a dream come true."
Irishman Dunne was playing at Kingsbarns and turned in 36 with a gain on the tenth and a bogey on the 14th but picked up further shots on the third and sixth.
Donald was also playing at Kingsbarns and he birdied the 13th, 16th and 17th before dropping a shot on the first but made four birdies in five holes from the fourth.
Fisher was one under for his round after 14 holes but finished with four birdies for a 67 at Kingsbarns.
Thai Kiradech Aphibarnrat, Belgian Nicolas Colsaerts, Swede Joakim Lagergren, Frenchman Alexander Levy and German Bernd Ritthammer were then at nine under.
Bourdy's performance helped him and amateur partner Aidan Heavey to 28 under and a one-shot lead in the team event over Joakim Lagergren and Billy Getty, Alexander Levy and Tom Jermoluk, and Yikeun Chang and Erwee Botha.