Padraig Harrington, two shots off the 66th US Masters lead at Augusta after the first round, believes a cautious approach was to blame for allowing his early lead to slip on the homeward nine.
Harrington, playing in the Masters for only the third time, went out in a blistering 31 and then holed a 12-foot putt on the 490-yard par four 11th to take a commanding lead.
At six under the 30-year-old, never higher than fifth in any major championship, led by three.
But he took six on the long 13th, hitting his second into Rae's Creek off a perfect drive, and bogeyed the 14th and 18th as well for a three-under 69.
Harrington said afterwards: "I was a bit cautious after the 12th and that was undoubtedly my downfall. But I would take 69 any day here. There is adrenalin and butterflies on the first tee of the Masters, but I don't think I had any more after 11 holes.
"When you are six under you are trying to get to seven under. You can never get complacent out there, though," he said.
"I don't know what money there is for finishing second, but no amount is going to compensate you if you just miss out," he said. "We're not going there to make a living. We're going to win and the Masters is probably the worst tournament you can finish second in."
Davis Love III heads the leaderboard at the end of the first round having made the most of the benign conditions.
With little breeze and sunshine replacing the early morning clouds, the 37-year-old Love shot a five-under par 67 to hold a one stroke lead over Spain's Sergio Garcia and Argentina's Angel Cabrera.
Two shots back, alongside Harrington, are US Open champion Retief Goosen of South Africa and American Phil Mickelson, who seeks his first major title.
Three strokes back was a host of big-name stars including defending champion Tiger Woods, Ireland’s Darren Clarke Ernie Els, Jesper Parnevik, Jose Maria Olazabal, Phil Mickelson and Nick Price.
Paul McGinley bogeyed the first two holes of what was his Masters debut, but dug in and birdied the 15th and 17th for a level-par 72.
Belfast’s Michael Hoey, the reigning British amateur champion, is further down the field on three-over par.