Dustin Johnson turned in 33 to open up a four-shot lead on a wild third day of the WGC-HSBC Champions.
The World Number One entered round three with a one-shot lead over Brooks Koepka as he attempts to become the first man to win three World Golf Championships in the same season.
The American duo were tied at the top and six clear of the rest of the field stood on the eighth tee but with Johnson making a birdie to get to 16 under and Koepka recording a triple-bogey, it was last season's US Open champion who took command.
Justin Rose, Brian Harman and Kyle Stanley were then eight shots off the lead at Sheshan International Golf Club, with the European Tour quartet of Rafa Cabrera Bello, Tyrrell Hatton, David Lipsky and Henrik Stenson at seven under.
It was all change on the first as Johnson made just his third bogey of the week and with Koepka holing from just off the edge of the green, the reigning US Open champion was back in the lead he had held for most of round two.
All three of the final group then took advantage of the par five second, with Koepka holing from eight feet on the next for a birdie-birdie-birdie start and five gains in his last six holes.
Johnson would not let him get away, however, and holed a 15-footer on the fourth to get to 14 under.
A poor shot from the bunker on the seventh had Rose in some trouble and he dropped a shot, with Johnson getting up and down from a nasty lie to tie the lead, with the duo in top spot now six clear of the field.
There was then that huge swing on the par five eighth as Johnson put his second shot left but got up and down for an unlikely birdie and Koepka recorded an eight.
The four-time Challenge Tour winner lost his ball in the trees off the tee, put his fourth into more trees to the left of the green to take another drop, and two putts meant that Johnson had a four-shot lead.
Rose then got in trouble in the trees on the ninth for a second bogey in three holes.
American Stanley was three under after 13 holes while countryman Harman had picked up one shot in 11.
Lipsky was two under for his 14 holes despite a double-bogey after finding the water on the 13th, while Cabrera Bello and Hatton were both one under for the day after 12.
Matthew Fitzpatrick, Peter Uihlein and Matt Kuchar were then six under.
