A brilliant six under par 65 saw Rory McIlroy lead the US Open Championship – the third time in the last four Majors he has led after the opening round.
McIlroy did not drop a stroke all day, out-scoring playing partner Phil Mickelson by nine on the American's 41st birthday, and was in a league of his own as he led the field by three strokes after a dream start at Congressional.
The reigning Masters Champion, Charl Schwartzel, and 2009 US PGA Champion, YE Yang, are his closest challengers after opening 68’s while Open Champion, Louis Oosthuizen, and defending US Open Champion Graeme McDowell, were among those who also impressed, after opening their accounts with rounds of 69 and 70 respectively.
But the day belonged to the brilliance of McIlroy as he made light work of what is considered the toughest of the Major tests.
Not that it was the youngster's lowest start to a Major. At St Andrews last July he kicked off The Open Championship with a record-equalling 63.
McIlroy followed it with an 80, though - the same score as his final round at Augusta National in April after leading by four overnight.
The real test is yet to come, therefore, but there was no evidence of any lasting scars as he birdied the 12th, 17th and the monster 523 yard par four 18th for a back-nine 32.
He went ahead on his own with an eight footer at the 402 yard first, hit his approach to within three feet of the flag on the 470 yard fourth and then two-putted the long sixth for a sixth birdie.
A closing par on the 636 yard ninth as rain returned meant he matched the opening 65 of Colin Montgomerie in 1997 - a round the Scot rates his finest ever and one that was also watched by Mickelson.
McIlroy, who missed only one green in regulation, said: "I'm looking forward to tomorrow. I drove the ball well, my iron play was good.
"I just feel very comfortable with my game and on this course. When you have a combination like that everything is going to seem okay. But I have to back this score up.
"When I got here last Wednesday I felt the course was set up well for me and it's worked out.
"It does not feel like a typical US Open. It's going to get harder, firmer and trickier, but I still feel it's very playable."
Schwartzel finds himself in the hunt once again just two months on from his Augusta victory after picking up four birdies on his last nine.
“It's a long way to go, but it's nice to get yourself in contention,” he said. “It makes your work almost less. If you start falling too far behind on a tough golf course, things can get a little bit too far in front of you. So you need to stay in there with a chance.”
Sergio Garcia, who earned a place in his 48th consecutive Major through qualifying, three putted the last to drop to two under par 69 but showed he is back in form and a genuine contender with some great ball striking.
McDowell and Swedes Johan Edfors and Henrik Stenson had been the best of the early European starters with one under 70, later joined by Alvaro Quiros and last week’s BMW Italian Open champion Robert Rock, a remarkable achievement considering he didn’t play a practice round after issues with his visa.
He was in a tie for 11th and said: "I'm just starting to feel tired now. I'm looking forward to some sleep."
McDowell hit back from an opening bogey with two quick birdies and then 12 pars in a row.
He said: "I felt really good this morning. I set myself some challenges - to think well, go through my process and keep patient.
"I just tried to take each hole as it comes and all in all I'm very happy. They've taken this course to the edge and you can see some of the greens are stressed."
The Northern Irishman was halted in his progress for a while when a spectator needed medical attention on the 11th, but parring his way through the entire inward half - much the harder of the two - added to his confident mood.
Three-time Major winner Padraig Harrington would have been one under as well but for a closing bogey six at the long ninth.
He said: "I would have taken it before I went out. If I had birdied the last rather than bogeyed it I would have felt a lot happier, but it was a fair reflection.
"I've got a new set of irons and I definitely had a nice bit of control. They're next year's model, but I get them six months in advance."
Much focus was one the world's top three of Luke Donald, Lee Westwood and Martin Kaymer and they returned two 74s and a 75 from Westwood.
Westwood lost vital ground with bogey sixes on the sixth and ninth - like McIlroy he also began on the inward half - said: "I didn't swing it very well and you just don't get away with it at a US Open.
"If we had played like the top three in the world it would have been more enjoyable for the people to watch, but none of us played well and we all just about got what we deserved."
Donald began spectacularly, hitting four irons to four feet on the dangerous short tenth and 14 feet to set up another birdie at the 494 yard uphill par four 11th.
But he then had four bogeys in five holes from the 13th and a double bogey six on the 18th, at 523 yards the second longest par four in US Open Championship history.
Although he came home in one under great damage had been done to his great expectations and he commented: "There were no fireworks - we just didn't get on a run.
"At times you need one of the guys to get everyone going and it just didn't happen today."
