Ireland's Paul Dunne described the British Open as like a "zoo" after blazing a trail for the amateurs with a second successive round of 69 to put himself in contention on Friday.
The 22-year-old's 138 total for 36 holes equalled the record of England's Justin Rose at Royal Birkdale in 1998 and South Korea's Jin Jeong at St Andrews in 2010.
It also put him on the first page of the leaderboard, rubbing shoulders with the likes of 2010 champion Louis Oosthuizen and former Masters winner Zach Johnson.
"In terms of why amateurs are doing well, I'd say if you put an amateur tournament on around here, people will be shooting scores to be up there on the leaderboard," Dunne told reporters.
"Maybe not up at the top, but certainly around top 20. But it's just hard when the atmosphere is like this. It's kind of like a zoo out there.
"Amateurs are well capable of shooting the scores needed to do well, it's just about controlling your emotions when you're out there, not letting it get to you."
Dunne made just one bogey in a measured round containing four birdies and at six under is now favourite for the silver medal awarded to the best amateur, although American Jordan Niebrugge also impressed again with a 73 to lie four under.
"That would be brilliant," Dunne, who studies at the University of Alabama, said.
"It would be nice to get the silver medal, my last year as an amateur. It would be something I would remember forever."
"But there's a lot of golf and a lot of bad weather to play in before that.
Meanwhile, England's Danny Willett set a testing clubhouse target, then revealed he was soon brought back to earth by his mother.
Willett is 41 under par for his last 10 rounds on the Old Course at St Andrews after adding a 69 to his opening 66 to reach nine under par, two shots ahead of Scotland's Marc Warren and former Masters champions Zach Johnson and Adam Scott.
But while the vicar's son from Sheffield is rightly entertaining thoughts of becoming the first English winner of the Open since Nick Faldo in 1992, his mother Elisabet kept Willett's feet planted firmly on the ground.
"I just had a text message off my mum saying well done, you've made the cut," Willett told his post-round press conference. "I'm sure there will be a few messages, I can feel my phone buzzing a little bit right now. But it might be a case tonight of turning the phone off and having a little bit of quiet time."
After play was suspended for more than three hours due to torrential rain flooding the course, Willett carded birdies on the second, fifth and ninth to reach the turn in 33, before another birdie on the 10th gave him a three-shot lead as Johnson dropped shots on the 11th and 12th.
Three-putt bogeys on the 15th and 17th cut the gap to a single shot, but Willett took advantage of the downwind 18th to drive to the edge of the green and pitched to eight feet for a closing birdie.
"I looked at the leaderboard on 11 and knew we were three in front," added Willett, whose best finish in a major is a share of 15th at Muirfield in 2013.
"It's a childhood dream and looking up there it's still a little bit surreal, but something I'm going to have to get used to, otherwise no point in being up there.
"You can't really put it out of your mind but it's pretty cool. Leading the Open is what you dream about. For Brits especially it's the major you want to win and here at the Home of Golf it's a little bit more special."
Willett won the English Amateur title in 2007 and defeated Rory McIlroy in the first round of the Amateur Championship the same year, racing five up after six holes before eventually sealing victory on the 17th.
And later that year he and McIlroy were on the same team in the Walker Cup as Great Britain and Ireland lost out at Royal County Down to an American side featuring Rickie Fowler, Billy Horschel, Dustin Johnson and Webb Simpson.
Willett, 27, claimed his second European Tour title in the Nedbank Challenge in South Africa last December, finishing with rounds of 65 and 66 to overturn a five-shot deficit to former world number one Luke Donald, and also reached the semi-finals of the WGC-Cadillac Match Play in San Francisco in May - losing to one of his playing partners at St Andrews, American Gary Woodland.
Warren matched Willett's 69 to boost Scottish hopes of a first home winner since Paul Lawrie, the 1999 champion among the late starters after an opening 66.
"I'm delighted with that," said Warren, who carded a closing 64 to finish fourth in the Scottish Open at Gullane on Sunday. "It was a long morning.
"I had just started my warm up in the rain and the good news came in it was going to be delayed. When we did tee off it was certainly much drier and it was just the wind we had to battle.
"The weekend of the Open at St Andrews does not get much better. The game is in good shape, I'll give it my best and see what happens."
South Africa's Jaco van Zyl hit the opening tee shot of the day at 6:32am and had a three-foot putt for birdie before play was suspended.
"They tried to squeegee the green but water was rising quicker than they could get it away," Van Zyl said. "We had the option to putt out but we all stopped, the hole was literally full with water."
The lengthy delay meant the last group yesterday was scheduled to tee off at 7:27pm, meaning the round would not be completed on schedule.
But chief executive Peter Dawson said the R&A would not employ a two-tee start, which was implemented for the first time in British Open history at Hoylake last year due to a bad weather forecast for the action on Saturday.
"We do have the ability to go into Monday (the last time that happened was at Lytham in 1988), but we certainly hope not to," Dawson said.