Roberto Castro fired a sizzling opening round of 10-under-par 62 to lead the PGA Tour's Sanderson Farms Championship by two strokes in Jackson, Mississipi.
Six of the 10 top-ranked players in the world, headed by Jordan Spieth and Jason Day, will compete in the Hero World Challenge in The Bahamas next month.
Rory McIlroy fired his third five-under-par 67 of the week to surge to within one stroke of the leaders after the third round of the Turkish Airlines Open.