Brooks Koepka made three birdies in his first four holes to edge ahead on day three of the WGC-HSBC Champions.
Koepka led for most of Friday until Dustin Johnson produced a back nine of 29 and the four-time Challenge Tour winner was a shot behind the World Number One overnight.
A birdie-birdie-birdie start moved him to 15 under with playing partner Johnson just a shot behind as conditions were once again perfect at Sheshan International Golf Club on Saturday.
Justin Rose was the third player in the final group and he led the Euroepan Tour challenge at ten under, a shot clear of Thailand's Kiradech Aphibarnrat.
Spaniard Rafa Cabrera Bello was then at eight under, a shot ahead of a group including Matthew Fitzpatrick, David Lipsky and Henrik Stenson.
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.
All three of the final group then took advantage of the par five second, a feat also achieved by Aphibarnrat as he moved into double figures along with Rose.
Cabrera Bello had gone one better than that, claiming his second eagle in five holes, and when he holed from 12 feet on the par three fourth he was five off the lead.
That was soon six as Koepka holed from eight feet 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.
Aphibarnrat dropped a shot on the fourth with Cabrera Bello making a bogey on the sixth as the leading duo threatened to split the field.
Lipsky was two under for his first seven holes with Fitzpatrick and Stenson both level par for their rounds.
Americans Brian Harman, Matt Kuchar and Kyle Stanley were also seven under.
