|Third round leaderboard|
|-12 P Dunne (Ire) (a), L Oosthuizen (SA), J Day (Aus); -11 J Spieth (US); -10 P Harrington (Ire); -9 M Leishman (Aus), J Niebrugge (US) (a), S Garcia (Spa), J Rose (Eng), R Goosen (SA), R Streb (US), A Scott (Aus), Z Johnson (US), D Willett (Eng)|
|Selected others: -8 E Pepperell (Eng), C Schwartzel (SA), S Bowditch (Aus); -7 D Johnson (US), M Warren (Sco), R Fowler (US); -6 P Lawrie (Sco). Full leaderboard|
|Monday's coverage: Live coverage on BBC One from 13:45 BST, Red Button from 13:30, Radio 5 Live from 13:00, online text commentary from 11:00.|
Just after 07:15 BST on Thursday, Paul Dunne, the 22-year-old amateur from Wicklow in the Republic of Ireland, walked on to the third tee at St Andrews and a thought struck him.
The graduate of the University of Alabama - the same school that Graeme McDowell attended - had just begun his Open Championship birdie-birdie and had caught sight of his name at the top of the giant leaderboard.
Sure, there wasn't exactly much to beat at that point. His was only the second group on the golf course, beginning at 06:43, but still he wondered if anybody at home managed to capture the moment for posterity.
"I hoped that somebody took a picture of the board on a computer screen to send to me later," he said.
In the early morning light of Thursday he couldn't know that by nightfall on Sunday his name would have returned to the number one slot, level with Louis Oosthuizen, the 2010 Open champion at St Andrews, and Jason Day, so close so often to winning a major, and ahead of a battalion of the biggest names in the sport.
What Dunne achieved in his third round was breathtaking, his six-under 66 sitting alongside his pair of 69s for a 12-under-par total.
He said that it was a "surreal" feeling leading the field. It was only at the end of June that Dunne put himself in danger of missing Open qualifying at Woburn, failing to calculate properly the travel time to the course. He made it and he won it, beating Retief Goosen in the process.
Once again Goosen is trying to chase the Irishman down. The South African, who has won two US Open titles, is on nine under, among a group of heavyweight pursuers.
"It's surreal but I can easily believe that I shot the three scores that I shot," explained Dunne. "If we were playing an amateur event here I wouldn't be too surprised by the scores I shot. It's just lucky that it happens to be in the biggest event in the world.
"Hopefully I can do it again, but whether I do or not, I'll survive either way.
"I'm not really going to think about winning or where I'm going to finish until the last few holes on Monday. I can't control what people do. Everyone could shoot 63 or everyone could shoot 75."
|Amateur winners of The Open|
|Harold Hilton||1892, 1897||Muirfield, Royal Liverpool|
|Bobby Jones||1926, 1927, 1930||Royal Lytham & St Annes, St Andrews, Royal Liverpool|
Can he win? "I don't see why not," he replied. "I mean, I'm well capable of shooting the score that I need to win if everyone else doesn't play their best. Hopefully I play great again."
Dunne has become an adopted son at St Andrews, his underdog status appealing hugely to the galleries who followed him in numbers and applauded him to the rafters. "I felt like I had so much support from the crowd," said the Irishman. "I felt like I was at home. Every shot I hit was getting cheered."
All day we waited for his challenge to falter, but it never did. He birdied five of his first 10 holes to propel himself into the lead on 11 under, then picked up another birdie on 16 to get to 12 under.
"I went out there thinking that if I could play sensible and keep the bogeys off my card I was going to have opportunities for birdie and I was bound to make some," he added.
He was bogey-free. Flawless and nerveless.
You looked at his slight 5ft 8in, 11st 6lb frame and wondered how he could carry the pressure burden so lightly, but he did.
By day's end we were reaching for the history books and thumbing our way back to 1930 to find the last amateur who won The Open - the immortal Bobby Jones. We journeyed onwards from then to remember all those other amateurs who tried and failed in Jones's wake and hit on quite a list.
Dunne's chances of actually winning the Claret Jug remain improbably high given the outrageous quality of the chasing pack, but it's no harm to place into context what he's attempting to do in Monday's final round.
The list of amateurs who tried and fell short in the oldest major is as stellar as it is long.
Bobby Locke, the great South African, finished eighth at Hoylake in 1936, Frank Stranahan, the remarkable American, finished second in 1947, also at Hoylake.
Sir Michael Bonallack, Sandy Lyle, Jose Maria Olazabal, Phil Mickelson, Justin Leonard, Tiger Woods, Justin Rose, Sergio Garcia, Luke Donald, Rory McIlroy. They all showed up as amateurs, some played majestically, some less so, but none won.
Rose, famously, came within two shots of Mark O'Meara at Birkdale in 1998, but Dunne's situation atop the leaderboard puts him in Jones territory.
One of the men chasing him is a hero of his, his countryman Padraig Harrington.
"Padraig's probably been the most influential person in Irish golf in modern history," said Dunne. "I remember watching him win The Open at Carnoustie in 2007 and 2008 at Birkdale. I've watched those videos over and over again. So has everyone in my family. I've always looked up to Padraig."
The double Open champion described Dunne as "phenomenal" and "incredible".
Dunne was still on the golf course when Harrington completed his own brilliant seven-under-par round of 65, for 10 under, and shook his head in amazement at the young man's quality.
"He's led The Open Championship a long way into the event - as an amateur," said the 43-year-old Dubliner. "That is as rare as it comes. If I don't win, I hope he does."
Everybody loves Harrington - and what a story he would be if he was to win a third Claret Jug after so many dog-days in recent times.
There are other great stories on the leaderboard but only one Cinderella story. If Dunne holds it together and manages to do something that nobody thought possible it would truly be the golfing fairytale to beat all golfing fairytales.