Tyrrell Hatton will take a commanding three-shot lead into the final round of the Alfred Dunhill Links Championship after posting a sensational 62 on Saturday to equal the course record at St Andrews.
The Englishman fired ten birdies and no bogeys at the Old Course on day three to propel himself to the top of the leaderboard.
Fellow countryman Ross Fisher, who led at the halfway stage, is Hatton's nearest challenger on 14 under after producing a 69 at Carnoustie.
Sweden's Joakim Lagergren and South African Richard Sterne are a further shot back, just ahead of German duo Martin Kaymer and Florian Fritsch on 12 under.
Hatton, who began his third round four shots behind overnight leader Fisher, got off to a flying start, making gains at four of the first six holes to move into contention.
Successive birdies at the eighth and ninth took Hatton to the turn in 30 and handed him the outright lead.
A birdie at the 12th saw Fisher regain a share of the lead but Hatton was alone at the top of the pile once more after sinking his birdie putt from close range at the tenth.
After safely parring the next three holes, Hatton sent his approach at the 14th to within eight feet and tapped in for a birdie.
The 24 year old drained a monster putt to pick up another shot at the 17th before tapping in from a couple of feet for a birdie at the last to get to 17 under.
It's quite clearly the best round I've ever had - Tyrrell Hatton
Hatton, who is still searching for his first European Tour victory, was delighted with his score on Saturday. He said: "It's quite clearly the best round I've ever had. I've never actually got to double digits before, either, so very pleased with that.
"I putted really well again today. That was the big thing. Just kept momentum going with holing some good birdie putts and holed a couple of good par putts as well. That kept things going and I'm really happy with that finish.
"Obviously I'd love to get a win. I'll try my best tomorrow. It's been a really consistent year and it would be nice to have a good finish to the year."
Fisher covered his front nine in 35 after carding birdies at the second and sixth as well as a bogey at the third.
The 35 year old rolled in from four feet at the 12th before adding another birdie at the next.
Fisher regained the outright lead when he holed his 20-foot birdie putt at the 15th but a dropped shot at the 16th saw him finish on 14 under.
He said: : "It was decent. You never know what you're going to get when you turn up here. We were all hoping for Car-nicety and not Car-nasty. We got it.
"It was a beautiful day to play this place. What a golf course in this condition.
"Conditions were pretty benign. There wasn't much breeze. So whether it played easier or harder than what the other guys had it, I don't know.
"I heard stories about some of the clubs they were hitting onto the par fives and obviously we had it a lot longer and the tougher holes played easier for us.
We were all hoping for Car-nicety and not Car-nasty. We got it - Ross Fisher
"It was still tricky out there. It was very firm, very fiery, but yeah, overall, I felt pretty pleased with the round. There were a couple of scrappy shots.
"I maybe left a couple of putts out there but you know, all in all, I can't complain. It plays pretty good, and to shoot under par and shoot in the 60s for the third day running, I'm obviously very, very pleased."
Meanwhile, home favourite Marc Warren sits seventh on 11 under after mixing nine birdies with four bogeys at Carnoustie on Saturday.
