Jordan Spieth felt he paid the price for his "15-is-a-birdie-hole mentality" after a dismal nine at the par five dented an otherwise solid opening to the Masters.
The American returned to Augusta for the first time since an implosion at the 12th last year ended his hopes of retaining the title he won in 2015.
Spieth negotiated that hole well to make par, before carding a birdie at 13 which left him briefly in a share of the lead.
But that was as good as it got for the 23-year-old.
The wheels came off at the 15th when his third shot span back in the water, while his sixth was left well short of the flag and he three-putted from there.
Spieth eventually recovered to sign for a three-over-par 75, leaving him six behind clubhouse leader William McGirt, but he was left to rue his decision-making.
"Yes [15 was very difficult]. You think of it as a birdie hole, obviously being a par five," he said.
"Unfortunately I still thought of it as a birdie hole and it really isn't, when you lay up. So I didn't take my medicine and hit it about 15 feet right with a club that takes the spin off.
"Instead I was stuck in the 15-is-a-birdie-hole mentality and it kind of bit me a little bit. I struck the shot well, I just hit the wrong club.
"I struck it very solid, I used a club that would spin instead of one that would maybe take the spin off.
"I moved up a few, 10, 15 yards on the next one and I clubbed down and that one just didn't hit the same wind.
"But you don't have much depth there and I obviously wasn't going to hit it in the water again. So I just went over and from there it's very difficult."
Asked what was going through his mind as he approached the 12th, Spieth replied: "I always have nerves walking to that tee, I always have.
"It was a tough because you don't know exactly what the wind is going to do to the ball. I ripped one. I was very surprised at how far it flew and how little the wind affected it.
"But I think if we hit it three minutes later the ball could have been in a totally different location. So it's just a challenge because you don't know exactly where it's going to land in mid-air, so that creates nerves walking up to the tee."