Tommy Fleetwood broke the course record at Carnoustie to join defending champion Tyrrell Hatton at the top of the leaderboard after two days of the Alfred Dunhill Links Championship.
The Race to Dubai Rankings presented by Rolex leader is playing his first event since the birth of son Franklin last week and celebrated with a 63 to get to 11 under.
That moved him alongside fellow Englishman Hatton who fired a 65 around the same layout as he continued his recent return to form.
Fleetwood is playing just his fourth event since July but showed no signs of rust as he looks to cement his status with the battle to be Europe's number one reaching its closing stages.
Belgian Nicolas Colsaerts carded a 67 round the Old Course at St Andrews to get to ten under, a shot ahead of last week's winner Paul Dunne and German Marcel Siem.
Fleetwood birdied the second, fourth and sixth but really came to life as he made five birdies in a row from the 11th. After gains on the 11th and 12th, he hit an excellent tee-shot into the par three 13th and holed from 15 feet.
The 14th was proving extremely gettable and the 26 year old took advantage of the par five before hitting the pin for a tap-in on the next. He nearly holed from the edge of the green on the 16th before an eight-footer on the last put him in the history books.
"Any time you have a course record, especially on a golf course like this, it's brilliant to have," he said. "I'm very proud at the moment.
"I played well, putted well. It just unravels really, sometimes it does that. Most of the times, those are your best rounds when you don't quite realise what you're doing.
"I would love to win a tournament. I'd love to win this tournament. The goal every week is to try and win whatever you're playing in.
"With such big events coming up, I don't think anything will be over until it's finally done but if I can keep making that cushion a little bit bigger, then it will feel a lot nicer."
Hopefully I can have a good one at Kingsbarns tomorrow and all to play for for Sunday - Tyrrell Hatton
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.
The 25 year old made a hat-trick of birdies from the sixth and after parring the 12th despite losing his ball off the tee, claimed another gain on the 13th.
He made a two-putt birdie on the 14th before chipping in at the 16th despite sending his tee-shot a long way left and closed with a long putt on the last.
"Happy with today's round," he said. "Got lucky a couple of times but obviously you need that. The putter came alive for me on the last sort of 13 holes.
"It's a strange feeling to think I've won the tournament, because when I look back, it doesn't feel like it was me that won. It's great to be back and good memories from last year.
"I've come into this event with a bit of form. I'm happy that I'm sort of carrying it on and, you know, hopefully I can have a good one at Kingsbarns tomorrow and all to play for for Sunday. But there's still a lot of golf still to be played."
Colsaerts birdied the tenth, 11th and 18th to turn in 33 but found the Swilcan Burn on the first to undo much of that good work with a double-bogey. Birdies on the second, fourth and fifth were a stunning response and when the big-hitter drove the ninth and got down in two, he was into double-figures.
Irishman Dunne had to recover from an early bogey on the second at Carnoustie and made birdies on the third, sixth, tenth and 12th. He nearly put his second in the bunker on the 14th but got down in two for birdie and rolled in a long putt on the 16th before a disappointing bogey on the penultimate hole.
Siem birdied the tenth and then made four birdies in five holes from the 18th before holing a long putt on the ninth.
Thai Kiradech Aphibarnrat, Scot David Drysdale, Swede Joakim Lagergren, German Bernd Ritthammer and England's Matt Wallace were then at eight under, a shot clear of England's Ben Evans and Frenchman Grégory Bourdy.