Charley Hoffman, who qualified for the event by winning last year's Texas Open, sank four consecutive birdies on his way to firing a seven-under par 65. Photograph: (AFP)
Charley Hoffman has a four-shot lead, while former champion Spieth had a nightmare in the back nine
Unheralded Charley Hoffman snatched the first-round lead at the Masters on Thursday as high winds punished the world's top golfers and favorite Dustin Johnson withdrew injured.
Hoffman, 40, posted a seven-under par 65 in conditions described by one former Masters winner as 'borderline' unplayable. He took a four-stroke lead on a day of high drama that saw world number one Johnson pull out following a freak accident.
Johnson had a serious fall on the eve of the tournament and despite showing up at the course and practicing his swing ahead of his scheduled tee time, decided the pain from a lower back injury would prevent him from competing at his best.
"I'm very sad I have to do it but it's just a freak accident. I wanted to try and play but I'm not going to be able to compete," he said.
"It just sucks."
Hoffman, with one top-10 finish this year, put together a run of four birdies over the back nine to open an impressive lead over fellow American William McGirt.
England's Lee Westwood, 43, still looking for a major title after 75 starts, was in third place a shot further back on 70 on a day when top contenders suffered in difficult conditions on the 7,435-yard Augusta National course.
Reigning US Open champion Johnson had been the oddsmakers' favorite in the year's first major golf championship after winning his three prior starts but hurt himself in a fall down stairs Wednesday at a rental house.
Without the world number one, Northern Ireland's second-ranked Rory McIlroy and Australian world number three Jason Day were tipped to be key contenders for the title.
However, neither had it their own way in the opening round, played in sodden blustery conditions.
Nor did another top contender, former Masters champion Jordon Spieth, who suffered a repeat of last year's quadruple-bogey disaster.
The 2013 Masters champion, Adam Scott of Australia, said the conditions were beyond tough.
"It's very difficult conditions and borderline (unplayable)," he said after returning a three-over 75.
Steady but swirling winds above 20 mph (32 kph) with gusts twice that speed sending tee shots and approaches soaring off target and even kept balls rolling on greens.
Four-time major champion McIlroy appeared to be struggling in the wind and was three-over after the front nine.
He opened with a bogey on the first hole and dropped shots on the third and fifth to make the turn in 39. But on the way back he sank three birdies to salvage a 72 and a share of 12th place.
He was one shot behind England's 2013 US Open champion Justin Rose, who was in an eight-way share of fourth on 71.
Day also suffered in the conditions, returning a two-over 74 with a double-bogey on the 11th hole to share 26th place.
For 2015 Masters champion Spieth, the day turned sour on the back nine in a near repeat of the quadruple-bogey nightmare that cost him back-to-back titles last year.
The American, twice a Masters runner-up, had been five shots ahead on the final day last year before he imploded after taking seven shots on the par-3 12th.
This time out, he negotiated the 12th hole in regulation but took a nine on the par-5 15th, ballooning his score before sinking a birdie at 16 to limit the damage to finish on 3-over 75.
Spieth said the bogey blowout put him under pressure for the following three days.
"I feel like I need to snag something tomorrow," he said.
One man who thrived in the conditions was former Masters champion Phil Mickelson, who fired a 71.
The 46-year-old US left-hander will replace Jack Nicklaus as the oldest winner in Masters history if he can collect a fourth green jacket on Sunday.