Amateur Tom Lewis and joint overnight leader Thomas Bjorn lost their magic today and threw the 140th Open Championship at Sandwich wide open.
Lewis saw 61-year-old playing partner Tom Watson hole-in-one at the sixth in the day's most electrifying moment, but his own 74 - nine more than his lowest-ever round by an amateur in the event - dropped him off the leaderboard.
And with Bjorn, the Dane who lost the 2003 Open at the course from three ahead on the 15th tee, handing in a 72 that for a while was in danger of being much worse it was all change at the top.
The clubhouse target was set at "only" four under par by Darren Clarke, trying to take his own ride on the wave of Irish success in golf these last few years.
Fourteen years on from his runner-up finish at Royal Troon and a decade on from his last top-10 finish in any of the majors, the 42-year-old Ulsterman sank a 20-foot birdie putt on the last for his second successive 68.
While world number two Lee Westwood and twice winner Padraig Harrington waited to discover if four over par was good enough to survive the halfway cut, Clarke said: "It would mean an awful lot to win.
"But obviously this is only after two rounds - there is an awful long way to go yet.
"And I believe the forecast for the weekend is very, very poor. I quite look forward to that, but the course is going to play very, very tough.
"If that's the case, then the tournament is still wide open for an awful lot of players and will be."
His round began with laughter.
"That was somebody whistling at me when I was bending over stretching," he explained. "I said 'I hope that was a lady', but he whistled again, same guy. I'm doing something all wrong."
Not in his personal life, though.
Five years after losing his wife Heather to breast cancer he is engaged to Alison Campbell, a former Miss Northern Ireland he met in a blind date set up by compatriot Graeme McDowell.
"I've got a wonderful fiancee. Alison is a great girl and instrumental in my getting my life back on track."
Clarke owes his place in his 20th Open to taking the 30th and last exempt spot off last year's European Tour money list by less than £2,000.
After practising first with Westwood and then with new US Open champion Rory McIlroy - he stood level par with five holes to play - Clarke went about showing he still has what it takes, although his second circuit of the Kent circuit was a real rollercoaster.
A double bogey on the fourth, where a chip came back down a steep slope, was cancelled out by an eagle putt of around 80 feet just three holes later.
Four birdies and three bogeys followed, but he had the lead in the clubhouse on his own for a mere 10 minutes.
In the following group America's 2009 US Open champion Lucas Glover, without a top-20 finish in five previous trips to the event, parred the last eight holes for a 70.
Most early eyes, though, had been on Young Tom and Old Tom - 20-year-old Lewis and five-time champion Watson.
Watson's ace with a four-iron was the 15th hole-in-one of his life, his four-iron hopping in on the first bounce.
The 2009 runner-up - he would have been the oldest major champion by 11 years if only he had parred the final hole at Turnberry - continued to amaze with a 70 to make his 24th Open cut and extend his own record as the oldest man to play all four rounds.
Lewis had a television camera in his face the moment he left the practice putting green and, not surprisingly in the circumstances, could not repeat his first day heroics.
He bogeyed the final two holes, avoiding going out of bounds on the last only by hitting a post, and the Welwyn Garden City player is still in the title hunt.
"I think if you asked me that two days ago I would have taken it, but at this moment it doesn't feel so good," he said.
Bjorn did well to limit the damage after a hat-trick of bogeys from the second.
"It wasn't the prettiest of days golf-wise, but I'll take where I stand in the championship right now," he commented.
World number one Luke Donald, meanwhile, was three over after 12 and could have a say in whether Westwood and Harrington were still around for the weekend.
More to follow...