Jordan Spieth shot a third-round 63 to take a seven-shot lead into the final day of the Hero World Challenge in Florida.
The American sank nine birdies in a bogey-free round on Saturday to finish the day on 20-under-par and surge clear of Keegan Bradley and Henrik Stenson in second place.
Patrick Reed, who himself carded 63 on Friday, failed to really build on that score as he shot 69 to head into Sunday on 11-under, nine strokes off the pace.
England's Justin Rose, meanwhile, sits fourth on 10-under, two shots clear of Australia's Jason Day.
