South African Richard Sterne led the way on a morning of spectacular scoring at the start of the Omega Dubai Desert Classic.
Ten birdies in his first 16 holes gave the five-time European Tour winner a two stroke lead over Scotland's Stephen Gallacher.
Scott Jamieson, Gallacher's compatriot, and England's Tommy Fleetwood were in with seven under par 65s, while Lee Westwood began his 2013 campaign with a confidence-boosting 67 - the same as 56 year old American Mark O'Meara.
Sterne, also playing for the first time this year, battled a serious back injury in 2010 and 2011, but was joint runner-up in the ISPS Handa Wales Open last June.
He birdied three of his first four, finished a back nine 31 with three more and then picked up further shots at the second, fourth, sixth and seventh to threaten the course record of 61 set by compatriot Ernie Els 19 years ago.
Gallacher had two eagles on his card. The first came when he sank his approach to the difficult 485 yard sixth and the other more conventionally on the long 13th.
Jamieson is the early leader of this season's Race to Dubai after finishes of first, third and second in South Africa, but missed the halfway cut in the first two legs of The European Tour's three-week Desert Swing.
He was off and running today with an eagle at the long tenth - his first - and added six birdies, but also dropped a shot at the first.
Fleetwood, 22, saved his European Tour card with a sixth place finish at November's South African Open and was delighted to go bogey-free.
Westwood, who has been working hard on his game after moving with his family to Florida, said: "You never know what to expect after a few weeks off and I played nicely.
"There are a few new clubs in the bag and they all behaved. I felt very sharp - no rust there at all and I probably played better than I finished off last year.
"It's quite soft out there and if you strike the ball well you can score low."
Former Ryder Cup team-mate Paul Casey, slowly rediscovering top form, stood seven under as well until three-putting his final hole for a 66, the same as playing partner Matteo Manassero.
Casey managed only one halfway cut in the first seven months of last season after dislocating his shoulder snowboarding in Colorado, but has had four top-ten finishes since then.
"I'm not particularly happy about that," he said of his finish. "But I played beautifully and the key to that was the driver.
"It's something I've been struggling with, so I am ecstatic about that.
"We had a letter last week about the condition of the greens, that they had picked up some disease, but they are absolutely pure and I'm not surprised the guys are going low."
Ex-Open champion O'Meara has been back every year since his 2004 victory and said: "I can't hit the ball like the kids can, but I'm still driving it a reasonable distance and I had high expectations of getting off to a good start."
Sterne had to settle for two closing pars, but while he missed out on the course record by one his 62 was the lowest round of his European Tour career.
Gallacher reduced the gap to one with three successive birdies from the 15th and with the par five last to come had hopes of at least joining Sterne at the top.
The 38 year old remained nine under, however, and so with a 63 equalled his lowest Tour round.
Last week's Commercial Bank Qatar Masters winner Chris Wood, paired with Westwood, handed in a 68, while of the later starters holder Rafael Cabrera Bello and Sergio Garcia, runner-up to Wood, stood level par after four.
Sterne said: "I knew Ernie had shot 61 quite a while ago and always thought it would be impossible to get close, but I got as close as you could.
"Hopefully I'll just keep going and give myself a chance on Sunday."
Gallacher stated: "It was a bizarre round. I chipped in, then three-putted from six feet, but I drove it great.
"My driver broke last week, but the new one is working well."