Hideki Matsuyama remains on course for a maiden World Golf Championships title, after a bogey-free 68 kept him three clear heading into the final round of the WGC-HSBC Champions in Shanghai.
Having carded a remarkable 19 birdies over the first two rounds, Matsuyama made gains at the second, ninth, 14th and 18th holes on Saturday to reach 17 under for the tournament.
The Japanese - who boasts top-five finishes in his last three starts - therefore remains three shots ahead of defending champion Russell Knox, who was also four under in round three.
Bill Haas, who had shared second with Knox overnight, slipped back into a tie for fourth with Francesco Molinari at 12 under, as Daniel Berger moved up to third - four behind Matsuyama - with a 67.
History in the making.-- The European Tour (@EuropeanTour) October 29, 2016
Hideki Matsuyama is aiming to become the first Japanese winner of a WGC event. https://t.co/MBhxR8gLuT
Haas initially cut Matsuyama's lead to one with three birdies in the first six holes, but bogeys followed for the American at the eighth and 11th.
Berger, meanwhile, charged into contention by picking up shots at four successive holes from the 13th, although his run of birdies was sandwiched by dropped shots on 12 and 17, enabling Knox to finish the day in sole possession of second.
A closing four provided the ideal finish for world number 10 Matsuyama, who once again prospered on Sheshan International Golf Club's par fives.
Rory McIlroy is eight off the pace, despite a remarkable birdie on the eighth that saw the world number three get up and down from a perilous position to the right of a water hazard.
Adam Scott followed up his eight-over 80 on Friday with an eight-under 64, while Matt Kuchar made a hole-in-one at the 17th, only to miss out on a car due to the tee having been moved forward.
Kuchar was quoted by the European Tour as saying: "Literally, a minute before my shot, I found out [there would be no prize]. I guess the way to describe it was the saddest hole-in-one.
"I knew I just made a hole-in-one and I was teased by this beautiful car sitting there, that's not to be mine."