Dustin Johnson struggled from the 1st tee on Sunday in Shanghai, opening with a bogey, and several hours later his six-shot lead had disappeared.
Justin Rose started the day eight shots off the lead and with a slim chance to knock off the leader, but he closed with a five-under 67 to win the WGC-HSBC Champions after Johnson failed to make a birdie and shot 77. During the entire 2016-17 season, Johnson shot that score or worse just twice on Tour.
"I felt fine all day," Johnson said. "I just could never get anything going and didn't hole any putts. It was pretty simple."
It was a rough day for the World No. 1. The six-shot lead he squandered tied the PGA Tour record for the largest lead lost entering a final round. It's the first time it happened since Sergio Garcia lost the 2005 Wells Fargo Championship in a playoff to Vijay Singh, and it's the second time it's happened to a World No. 1. The other? Greg Norman at the 1996 Masters.
Even Rose thought winning would be a long shot. He admitted he entered Sunday "playing for second."
Johnson bogeyed the first two holes and made the turn in two over. He then made bogeys on 12, 15 and 16.
"I didn't make any putts," he said. "I felt like I rolled it good. Just nothing was going in the hole. Hit a couple really bad iron shots. That was probably the key there on 14. I just chunked it. Same thing on 15; I just chunked it. That cost me two shots there. And then bogeying 16, that's just bad. So I just gave a few away. But tough conditions. But I mean, it is what it is."
Johnson missed out on becoming the first player to win three WGC events in one year. He won the WGC-Mexico and WGC-Dell Technologies in March. His five career WGC wins is the second-most all-time. Tiger Woods has 18.