RIDGELAND, United States (AFP) — Second-ranked defending champion Rory McIlroy, with a chance to return to world No. one, lurked one stroke behind American co-leaders Gary Woodland and Trey Mullinax after Thursday's opening round of the CJ Cup.

Woodland, the 2019 US Open champion, and Mullinax, who notched his first PGA victory in July at the Barbasol Championship, each fired a six-under-par 65 at Congaree Golf Club in Ridgeland, South Carolina.

McIlroy, who can overtake top-ranked Masters champion Scottie Scheffler with a victory, shot a bogey-free 66.