Top-ranked Jason Day is tied for the lead halfway through the second round of the RBC Heritage after shooting a 2-under 69 on Friday.
Day is tied with Kevin Chappell at 6-under par. First-round co-leader Luke Donald, who just began his round, is a shot back.
Day has won two of his past three PGA Tour events.
Day began on the 10th tee and made birdie on the difficult, wind-swept lighthouse hole at No. 18 at Harbour Town Golf Links. He added birdies on the second, third and sixth holes to move to the top.
Day acknowledged fighting through fatigue after a grueling Masters last week, where he finished 10th.