HILTON HEAD ISLAND, S.C. (AP) — Scottie Scheffler is running on fumes after an exhausting Masters victory just four days ago. He hit a shank from a bunker. He nearly lost his mind from mud on his golf ball. And he still managed a 2-under 69 at the RBC Heritage on Thursday.

J.T. Poston set the pace on an idyllic day on Hilton Head Island with nine birdies — six of them in a seven-hole stretch — for a 63 that gave him a two-shot lead over Collin Morikawa and Seamus Power.

Ludvig Aberg, the runner-up at Augusta, was in the group another shot behind. Rory McIlroy birdied his last two holes to salvage a scrappy day with the irons for a 67.

Thousands of fans lined the fairways of Harbour Town to see Scheffler, the Masters champion who is going for his fourth win in his last five tournaments. There were times Scheffler didn’t look like the No. 1 player in the world, and he figured that would be the case with very little time to prepare.