Jason Day remains on course for his first BMW Championship title and the world number one spot after opening up a six-shot lead heading into Sunday’s final round in Chicago.
The Australian tied the all-time PGA Tour record with an 18-under 124 in the first two rounds and he picked up another two shots on Saturday with a third-round 69.
Another steady round for Day would likely seal a fourth win in six tournaments, which would see him replace Rory McIlroy at the top of the rankings.
The Northern Irishman began the round nine shots behind Day and only managed to claw two back with a four-under 67 to sit fourth, with American duo Scott Piercy and Daniel Berger one shot better off.
World number two Jordan Spieth carded a one-over 72 to lie 10 under overall as he saw his hopes of victory in Chicago - and his own chances of usurping McIlroy - slip away, with Englishman Justin Rose a shot further back after going round in 70.
Brendon Todd, playing alongside Day and Berger in the lead group, dropped dramatically from second to 18th after a nightmare five-over-par round of 76 which included a triple bogey on the fourth hole.
It would take a special effort from the chasing pack to haul down Day, who is on the brink of becoming Australia’s youngest-ever world number one at the age of 27.
The US PGA Championship winner recorded a birdie on the third hole at Conway Farms before he went bogey-birdie-birdie-bogey from the sixth to close the front nine.
It was a similarly mixed back nine for Day with shots gained at 12 and 14 and dropped on 13 and 15, although he finished with a flourish by birdieing the last.