Emiliano Grillo recovered from a rough start in cold weather for a 5-under 67 to build an early three-shot lead in the Arnold Palmer Invitational.
Grillo was 2 over through four holes, then ran off seven birdies. That included a 50-foot putt on the ninth hole, and a 40-foot putt on the 17th hole at Bay Hill.
Defending champion Jason Day was among a large group at 70. Only 10 out of 60 players from the morning tee times managed to break par.
It was the first tournament at Bay Hill without the beloved tournament host, Arnold Palmer, who died in September.
His grandson, Sam Saunders, received the loudest ovation when he teed off in the afternoon with Rory McIlroy and Brandt Snedeker.