England's Tyrrell Hatton hailed the best round of his career after equalling the course record at St Andrews to take control of the Alfred Dunhill Links Championship.
Hatton carded 10 birdies in a flawless 62 on the Old Course and will take a three-shot lead over compatriot Ross Fisher into Sunday's final round at the same venue, one of three used for the pro-am event.
The world number 53 raced to the turn in 30 and picked up further shots on the 10th, 14th, 17th and 18th to finish 17 under par in pursuit of his first European Tour title.
Graeme McDowell was best of the Irish but lies nine shots off the pace on eight under following a 67 today. Paul Dunne is next on six under after a 66.
Shane Lowry slipped down the field after following up yesterday's 68 with a 72 today and is on four under, while Padraig Harrington is two under after a 71. Cormac Sharvin is level par, Jack Hume two over, Michael Hoey three over and Paul McGinley four over.
"(It's) quite clearly the best round I've ever had. I've never got to double digits before either so I'm really pleased with that," said 24-year-old Hatton, who was fifth in the Open at Royal Troon and 10th in the US PGA Championship at Baltusrol.
"I think my bad shots, I didn't really get punished for them. I missed them in good spots and I just putted really well. If you are holing putts, you're always going to shoot a decent score.
"I think the putt on 17 was probably the best putt I holed today, 25 feet. But the majority of them were around six to 15 feet and if you keep knocking them in, it's certainly good for confidence.
"We were all hoping for Car-nicety and not Car-nasty. We got it. It was a beautiful day to play this place" - Ross Fisher
"Obviously I'd love to get a win and I'll try my best tomorrow. It's been a really consistent year and hopefully I can have a good finish to the year as well.
"I went out to the States (after the US PGA) because I was close to getting a PGA Tour card, but that didn't work out and I'm happy to be playing back in Europe."
Halfway leader Fisher, who lost a play-off for the Porsche European Open a fortnight ago, carded a 69 at Carnoustie to finish 14 under, with South Africa's Richard Sterne and Sweden's Joakim Lagergren a shot further back.
"You never know what you're going to get when you turn up here," Fisher said. "We were all hoping for Car-nicety and not Car-nasty. We got it. It was a beautiful day to play this place.
"It was still tricky out there. It was very firm, very fiery, but overall I felt pretty pleased with the round. There were a couple of scrappy shots. Maybe left a couple of putts out there but all in all I can't complain. To shoot in the 60s for the third day running, I'm obviously very, very pleased.
"Hopefully I'll be drawn with Tyrrell (on Sunday), because we're pretty good friends. We've spent quite a few evenings together for dinner and stuff.
"I'm sure we'll go out there and have some fun and put on some good golf for the public and you know, whether it's me, him, someone else, there's going to be a worthy winner come tomorrow afternoon."
Former world number one Martin Kaymer is five shots off the lead after a 65 on the Old Course, but was more concerned with making the cut in the team event with his father Horst.
"I was quite a few shots behind, so the main goal was to make the cut with my father today," Kaymer said. "I know how hard he's trying and we played the last few years and we always came one shot short.
"He never experienced the final round at St Andrews, so I think the most important thing is that we have a good time out there as a family."