The only consolation was a 6-under 66, which gave Johnson a three-shot lead over defending champion Ian Poulter going into the final round of this World Golf Championship. It was the final hole -- a three-shot swing -- that irritated the 29-year-old American.
On a Sheshan International course set up for low scoring, Poulter made birdie on the par-5 18th for a 63. Three groups later, Johnson hit a bad drive at the worst time and watched it sail to the right and into the lake. Wanting to be sure he didn't drop it in the wrong spot, Johnson returned to the tee and wound up with a double bogey.
It was his second double bogey of an otherwise remarkable round.
After making five straight birdies to start to pull away, Johnson saw his wedge roll back down the hill three times before the fourth one hit the pin at No. 10. He still had to make about a 12-foot putt to escape with double bogey.
Johnson was at 18-under 198 and will be in the final group with Poulter and Graeme McDowell, who had a 64 and was four shots behind.
"I have to do my thing tomorrow," Poulter said. "It's only Saturday. You can't win tournaments on Saturday. It's all about playing well on Sunday. I need to do that. I need to make plenty of birdies, try to make an eagle. If I can, I can get close."
Rory McIlroy birdied three of his last five holes for a 67 and was six shots behind, along with Graham DeLaet and U.S. Open champion Justin Rose, who each had a 65.
They still had an outside chance, though so much of that depends on Johnson and how to he responds to his pair of double bogeys.
"I'm still a little mad from my double bogey on 18," Johnson said. "Obviously, to have a three-shot lead going into the last day is good and I'm looking forward to the challenge. I still have to play really well. The guys that are right behind me, they're playing very well, too. So it's still going to be a tough day tomorrow. Got to come out and make a lot of birdies."
That wasn't the problem -- for Johnson and most everyone else.
Martin Kaymer, who won the HSBC Champions two years ago by tying the course record with a 63 in the final round, went one better. The German started with six birdies in seven holes and thought briefly about a 59 with three straight birdies on the front nine that put him at 10-under with three to play. He missed an 8-foot birdie on No. 7, failed to birdie the par-5 eighth and had to settle for a course record 62.
Kaymer was eight shots behind.
"I've shot 59 before and I thought, `There's a chance,' especially after my birdies on 4, 5, 6," Kaymer said. "But you can't make them all."
McDowell was six shots out of the lead when he finished, exasperated that he could shoot 64 and not make up any ground. Even so, he has a lot at stake on Sunday at No. 2 on the European Tour money list, and he could move past Henrik Stenson to finish alone in second.
"From here, it looks like Dustin is going to have to beat himself for anybody to have a chance to catch him," McDowell said. "Race to Dubai points will be very important to me. I have a lot to play for tomorrow. If not the trophy, second place will certainly be worth my while."
And then, the trophy became a little more realistic.
Johnson looked unstoppable on the front nine with six birdies in seven holes, and he pounded his drive down the left side of the 10th that just crawled into the rough. He was trying to land beyond the flag, but his wedge came out dead and rolled back down the hill.
"Didn't hit the first one hard enough. Didn't hit the second one hard enough," Johnson said. "I think I hit the third one hard enough to get there."
His lead was down to one shot on the back nine until Poulter made bogey on the 17th, and Johnson went on another tear -- a 5-iron into 15 feet for a two-putt birdie on the 14th, another 3-iron on the par-4 16th that set up a chip-and-putt birdie.
And then came that one swing at No. 18.
Johnson, with a remarkable talent for being undaunted by a shot into the water, reloaded and hit a hard draw down the right edge of the water that found the fairway. Any chance of escaping with bogey, maybe even par, ended when his approach went into the bunker near a lip. He blasted out to 15 feet and took two putts for his 7.
Johnson had to be reminded that he still shot 66. He still had a three-shot lead.
"It's a good score," he said. "I'm definitely happy with what I shot. I'm just not happy with the way I finished. Making two doubles, there's no excuse for that, especially the way I'm playing right now."
