A year on from his dramatic final-round implosion on the 12th at Augusta, Jordan Spieth endured another nightmare hole at the Masters - making an abject nine on the par-five 15th.
Spieth, who became the favourite for the year's first major following the withdrawal of Dustin Johnson due to a back injury on Thursday, initially made solid progress as winds made life tricky in round one.
However, after making par on his return to the 12th and then birdieing 13 to climb into a share of the lead, Spieth's round unravelled in dramatic fashion.
The 23-year-old Texan bogeyed 14 before making an absolute mess of the next hole, his troubles starting when his third shot spun back into the water in front of the green.
Spieth's next pitch flew over the back of the putting surface and further problems followed as he played a poor chip before three-putting for a quadruple-bogey.
As a result, Spieth found himself four over, seven adrift of one of his playing partners, Matt Fitzpatrick. The Englishman made birdie at 15 to take sole possession of the lead at three under.
To his credit, Spieth bounced back impressively by birdieing the short 16th, courtesy of a superb tee shot, but the 2015 champion had left himself with much work to do.
Justin Rose and William McGirt represented Fitzpatrick's closest challengers, trailing the youngster by one, while Rickie Fowler and Phil Mickelson were among those a shot further back.
Thomas Pieters three-putted the 18th to finish level par, having been five strokes better off through 10.
Rory McIlroy bogeyed two of the first three holes in the company of rising star Jon Rahm, who looked far more solid as he started with a succession of pars. Jason Day was three over through 14.