Two-time champion Tyrrell Hatton tied the St. Andrews course record of 61 to lead the Alfred Dunhill Links Championship by one shot heading into Sunday's final round.
Hatton, who is seeking to become the first man to win the tournament three times, made an eagle and nine birdies on Saturday to reach 22 under par.
The Englishman also leads the pro-am team event alongside his father Jeff on 38 under.
"It was a cool day," said Hatton. "I had actually shot 10 under here before. So I really wanted to birdie the last.
"That's actually my lowest round on tour as well. Felt like I was trying harder than I normally would for a putt on the last."
Belgium's Nicolas Colsaerts sits second on the leaderboard after making an albatross at the par-five 16th at Kingsbarns on his way to a third straight 65 of the week.
Frenchman Tom Vaillant is three off the lead at 19 under.
Rory McIlroy, who was playing alongside his father at St Andrews on Gerry McIlroy's 65th birthday, fired a 68 to sit at 10 under.
After playing one round at each of St. Andrews, Carnoustie and Kingsbarns, those left in the field all take on the Old Course at St. Andrews on Sunday.
Among the amateurs taking part this year were PGA Tour commissioner Jay Monahan and Yasir Al-Rumayyan, the governor of Saudi Arabia's Public Investment Fund, which bankrolls the breakaway LIV Golf series, fuelling speculation a breakthrough could be imminent in negotiations over the future of the sport.
However, they will not be in action on Sunday after their teams finished well outside the 20 pro-am teams that advance.