Henrik Stenson led the Masters for much of the first day but a quadruple bogey on the 18th saw him fall from five under to finish on one under.
"I hit it way left off the tee, a low hook, and the ball was playable in the bushes, so I went in and found a small gap but didn't get it out," he said.
"The worst part was hitting the wedge up in the crowds behind the green.
"It took me four to get down from there. But finishing with an eight, I don't think I've ever done that."
"But that's what happens here. It keeps on snowballing and I got the snowman at the end," added Stenson, who finished four behind first-round leader Lee Westwood.
Favourite Tiger Woods fared better on the last, turning an unplayable lie into a better-than-expected bogey on the last hole to close out a round of even-par 72.
"I hit some of the worst golf swings I've ever hit today, and that's all right," said the American world number seven after his bogey on the last, which followed another on the 17th, dropped him off the leaderboard.
"I just hung in there and grinded my way around the golf course and stayed very patient, stayed in the moment.
"Unfortunately that was about as good as I got right there. I could have shot one, maybe two better, but I got a lot out of that round."
Northern Ireland's Rory McIlroy, the US Open champion and world number two, ground his way round Augusta before sinking birdies at the last two holes to finish one under.
"I'm a lot more pleased coming off the golf course than if I had finished par, to come off under-par is pleasing," said McIlroy.
"My perseverance and patience paid off and it was nice to finish as I did, but I'm surprised someone didn't go lower than five under today."
Ireland's Padraig Harrington went one better than Woods with a one under 71.
"I'm pleased," said the three-time Major-winner. "There are very few players burning it up.
"Conditions are very good out there for scoring in terms of there's no wind and the greens are soft. But I think they were aware of that and put in some tough pins.
"While you can go at every pin out there, if you're slightly out, you've got your work cut out to make a par."
Scot Paul Lawrie, playing the event for the first time since 2004, eagled the 13th and 15th for a three-under 69 that set the early clubhouse target.
"I'm still a little bit weak and not quite 100%," said the 1999 Open champion, who went down with bronchitis three weeks ago.
"I've played only nine holes every day [in practice] and worked a lot on my short game.
"I'm trying to keep it low key. I'm not thinking about winning at all - I'm three behind already!"
Ian Poulter, who also ended his round on one under said: "I played nice today. It was always going to be tricky. The pins were tucked away and that made it difficult early on. A lot of pins on the first six holes were tough to get at.
"The rain has made them want to protect the course score wise, the answer was to tuck the pins away but I played pretty solid today and I'm happy with that round.
"It's an early start tomorrow so hopefully I can get the best of the weather and the storm will have blown through. I can go out there and play aggressive."
Graeme McDowell was less pleased with his round of 75 that leaves him three over.
"It wasn't very good," he said. "I just don't play well around this golf course. It doesn't set up well for me. I'm not driving it well enough. I'm short with not enough right to left shape.
"It was tough today. The course played long and the pins were tricky and I just hit it in all the wrong places all day. I paid the price.
"I got off to a bit of a sloppy start with a bogey on one and a double on four and I was battling from there.
England's Justin Rose, tipped by many to be a contender in Augusta after arriving in Georgia with victory at the WGC-Cadillac Championship last month, ended his first round level.
"I didn't hit many loose shots, but I didn't hit many great shots either," said Rose. "I wasn't comfortable with exactly where I was going to miss the ball. I probably played a lot of conservative shots.
"I got off to a decent start, had a lot of 10-footers early in my round but missed them all high. I was giving the greens a little bit too much respect.
"There's no damage done. I can build on it from there. I'm not disappointed. I've got a few things I want to work on on the range, but it's very hard to keep your game on song for four days."