English amateur Tom Lewis and Danish veteran Thomas Bjorn lead the 140th Open Championship after the first round at Royal St George's.
Bjorn, 40, fired a five-under 65 on Thursday morning and was joined late in the day by the 20-year-old Lewis.
The pair lead by one from 47-year-old Spaniard Miguel Angel Jimenez, 2009 US Open champion Lucas Glover and American debutant Webb Simpson.
Northern Ireland's 2010 US Open champion Graeme McDowell and countryman Darren Clarke, England's Simon Dyson and Germany's world number three Martin Kaymer were in a large group on two under.
World number one Luke Donald struggled on the greens as he the same score as second-ranked Lee Westwood and US Open champion Rory McIlroy.
The 22-year-old Northern Irishman, carrying a huge weight of expectation following that stunning eight-shot victory at Congressional, got off to a nervous start and dropped two shots in his first three holes but fought back to play the last 15 in one under.
Bjorn, who blew a three-shot lead with four left to play when the Open was last played at the same venue in 2003, went out in 33 in a gentle morning breeze, which had dropped by the time Lewis came into the closing stretch, and picked up four birdies in five holes from the 12th before bogeying the last.
Lewis, who was named after Thursday's playing partner Tom Watson, hails from the same Hertfordshire town - Welwyn Garden City - as six-time major winner Nick Faldo.
And he showed similar qualities over the first round, which included four straight birdies from the 14th.
Lewis won the British Boys' Championship at Royal St George's in 2009 and shot rounds of 63 and 65 to finish three shots clear of the field in Local Final Qualifying at Rye.
A birdie two at the 240-yard par-three third was followed by further birdies at the long seventh and then the eighth as he steamed to the turn in three-under 32.
Dropped shots followed at 11 and 13 as at last it seemed the course was about to bite him back.
But Lewis still had something left in the tank with that sensational run of birdies which turned day one of the 140th Open Championship on its head.
"I don't even know what's happened out there," he told BBC Sport. "I didn't realise I'd made birdies from 14-17, when you're in the zone I guess you don't really notice but I'm thrilled to bits with the first round."
Lewis and Watson received a standing ovation walking up the 18th and the younger man said: "I didn't know if it was for me or the other Tom, all I needed to do was make sure I got up and down from the right side of the green and it was excellent, we don't get that for amateur golf or anywhere in the world for golf so I'm thrilled the fans are there."
Asked about his lack of preparation time for the event, Bjorn, only in the tournament as a replacement for injured Vijay Singh, said: "I decided to come down here and take it as a bit of a joyride really, if I did get in.
"You want to play in these championships and when I got in on Monday it gave me a bit of a boost.
"It might have done me a little bit of good just to get that kind of distance to it - and maybe enjoy it a little bit more."
Jimenez, meanwhile, was a model of consistency as he rolled in four birdies and went round the par-70 course without a single bogey on his card.
The Spaniard led the 2009 Open at Turnberry after a 64 on the opening day and although he could not quite match that effort, his performance was certainly good enough to give him hopes of bettering his best finish of third place a decade ago.
Afterwards, Jimenez spared a thought for former Open champion Seve Ballesteros, who died in May, but insisted it was now time for the game of golf to move on.
Images of Ballesteros are on display all around Royal St George's and he said: "The tribute to Seve here is very nice because we miss him, and he did so much for golf all through his life, and we have to thank him for what he did for golf.
"It's nice to make that tribute for him, but now I think is a moment also to start to concentrate on the golf tournament and keep moving on, because if not, you cannot play."