Former champion Phil Mickelson admitted he felt like crying after going agonisingly close to recording the lowest score in major history in the Open Championship at Royal Troon.
Mickelson, who has not won a tournament since lifting the Claret Jug at Muirfield in 2013, needed to hole from 15 feet on the 18th to card a nine-under-par 62, only to see his birdie attempt catch the edge of the hole and stay out.
The 46-year-old could barely believe it as he had to settle for a 63 - the 28th such score in majors - and a three-shot lead over American compatriot Patrick Reed and Germany's Martin Kaymer, with defending champion Zach Johnson a shot further back in an eight-strong group which also included England's Andy Sullivan.
Ryder Cup team-mates Justin Rose, Sergio Garcia and Henrik Stenson finished three under par and a shot ahead of Rory McIlroy, while Masters and US Open champions Danny Willett and Dustin Johnson - as well as Jordan Spieth - were level par.
Mickelson, who finished a shot outside the play-off the last time the Open was staged at Troon in 2004, had never shot lower than 66 in the Open before, with his last such score sealing victory three years ago.
But the left-hander took advantage of the wind dropping in the afternoon to card four birdies on the front nine and four more coming home as he looks to become the seventh consecutive American winner at Troon after Arnold Palmer, Tom Weiskopf, Tom Watson, Mark Calcavecchia, Justin Leonard and Todd Hamilton.
That would make him the fourth oldest major champion ever and the oldest at the Open since Old Tom Morris, who was just two months older than Mickelson when winning in 1867.
"This was pretty heartbreaking," said Mickelson.
"Nothing will match that final round at Muirfield, but it was one of the best rounds I've ever played and yet I want to shed a tear right now. That putt on 18 was an opportunity to do something historical. I knew it and with a foot to go I thought I had done it.
"I saw that ball rolling right in the centre. I went to go get it, I had that surge of adrenaline that I had just shot 62, and then I had the heartbreak that I didn't and watched that ball lip out. It was, 'Wow, that stings'. To have played this round and walk away feeling like I want to cry is a very awkward feeling."
Asked if he believed in the golfing gods, Mickelson said jokingly: "I didn't, but I do now. If there wasn't a curse, that ball would have been in and I would have had that 62."
Mickelson could find an advantage in today's 8.25am tee time before the weather is forecast to deteriorate, but added: "One of the biggest challenges is when you shoot a round like this, you start expectations running through your head and so forth, and that's the one thing that I'll have to try to suppress.
"We'll have varying conditions tomorrow. It's going to be very difficult. Hopefully I've prepared myself well enough to tackle this golf course under those conditions and shoot a good number. A good number might be over par."
Kaymer has not won since claiming his second major title in the 2014 US Open and lost his full playing rights on the PGA Tour at the end of last season, but is enjoying playing more in Europe.
"When you're an American you feel more comfortable in America," the former world number one said. "As a European, I love playing in Europe because every week is very different and every course that we play I enjoy the different cultures.
"For me, that is just the way I have to schedule my next few years. It took me 10 years to understand where is the best place for me to play my best golf."
Royal Troon member Colin Montgomerie hit the opening tee shot at 6:35am and bounced back from a double bogey on the first to finish level, but world number one Jason Day struggled to a 73 and 1985 champion Sandy Lyle slumped to an 85 to prop up the field.
England's Chris Wood was forced to withdraw after 12 holes with an ongoing neck injury.