Louis Oosthuizen had just closed to within two of the leader when he birdied the 12th as Mickelson dropped his first shot in 21 holes, but the South African then carved a fairway-wood into the hazard off the next tee, only for the left-hander to follow him into the drink with a wild duck-hook.
Although Mickelson conceded his ball had not crossed the hazard line before entering its watery grave and teed up another ball, but Oosthuizen was able to take a drop close to where his tee shot disappeared.
Overhead cameras suggested Oosthuizen’s ball had also stayed right of the red hazard line and should have also hit his third from the tee, but it was Mickelson who insisted his playing-partner was in the clear.
“His ball clearly crossed over the hazard,” said Mickelson, who ran up a double-bogey six as Oosthuizen escaped with a bogey-five.
“I didn’t think that was an issue. It flew down there, it had a big cut to it, and there was no question in my mind from where we were at that it crossed way up there. Mine was on the edge, and I just didn’t feel good about it. As much as it hooked, I just didn’t think it crossed it there.”
However, Oosthuizen did not discuss the incident, but he was more concerned by his standard of play throughout a third round in which he missed a number of short putts, although a level-par 72 kept him within striking distance of leader Mickelson on five under par.
“That was probably the worst I’ve played in a while,” said the 2010 Open champion Mickelson. “Especially the first 10 holes going along with Phil hitting it beautifully and playing great, I was all over the place. I could sense early on that I wasn’t on song, especially I felt a move in my driver that I didn’t like, and from there it wasn’t good.
“So I was just sort of fighting to stay in it, and at the end I started judging the greens wrong and everything just fell apart. All in all, two behind going into Sunday, I’ve got to take a lot of positives out of that with the way I was playing today.”