Niall Kearney moved into contention at the Hero Open, however, American Sean Crocker remains the man to catch at the Fairmont St Andrews, despite having his day-old course record broken by playing partner and temporary housemate Ewen Ferguson.
Crocker added a 66 to his opening 63 at Fairmont St Andrews for a halfway total of 15-under-par and a one-shot lead over Scott Jamieson, who fired eight birdies in a flawless 64 and has not dropped a shot over the first two days.
Kearney moved inside the top 15 with an excellent 66 to move to within five shots of the overall lead heading into the weekend.
The Dubliner started with a 68 on Thursday and got his second round going with three birdies in a row from the sixth to eighth holes, and while he dropped a shot on the tenth, he made four further birdies on the back nine to go around in six-under-par.
David Carey also impressed on the resort course of the historic old town by shooting 67 in a round that contained eight birdies.
Mr 57 - Carey shot that record score at the Cervino Open on the Alps Tour in 2019 - was struggling to make the cut following an opening round 71, however, his five-under second round sees him through to the weekend on six-under-par.
The other four Irish players in the field, Simon Thornton, Jonathan Caldwell, Paul Dunne and Cormac Sharvin, all failed to make it through to the weekend.
The round of the day belonged to Jamieson's fellow Scot Ferguson, who climbed more than 120 places on the leaderboard by following an opening 73 with a stunning 61.
Starting on the back nine, Ferguson followed a par on the 10th with six straight birdies and made another on the 18th to reach the turn in 29.
Further birdies on the second and third raised the prospect of just the second 59 in DP World Tour history, but Ferguson could only pick up shots on the sixth and ninth.
"I played incredible and putted a lot better than I have been," the 26-year-old said. "I’ve been working on that a lot with my dad and Goughie (Jamie Gough) to try and get the stroke right because the tempo was out.
"I still couldn’t get it then I woke up this morning feeling knackered and with not much hope (of making the cut) because the scoring had been so low. But Goughie came up to me with a piece of string that he put on the ground and told me to start hitting putts.
"I kept pulling it and he was telling me 'you are aiming left’ and I could see the line on my putter was aiming left. So he got me to put my hands forward and, though I felt it was abnormal, he took a video and I could see it actually looked normal and I started banging them in.
"That gave me a bit of hope on the greens when I headed out and I holed a good one for par on the 10th, then another good one for a birdie on the 11th. I could feel it suddenly.
"I missed the cut last week despite not playing badly but my head was down because I’d putted badly. Sean Crocker came to my house at the weekend to stay and me and him, my brother and a couple of friends had a night out and relaxed, really.
"Then I was drawn with him this week and I think that helped us chill out. He went out and shot a course record yesterday (Thursday) and I must admit I felt extra nerves playing with him today because of that and having a chance to beat it. It is pretty cool."
