With a 9-under 62, Troy Merritt equaled the Liberty National course record and took a one-shot lead over Dustin Johnson at The Northern Trust in Jersey City, N.J., on Thursday.
Kevin Kisner and Jon Rahm each fired a 7-under 64 to sit two shots back of Merritt after Round 1.
Rory McIlroy is among four players sitting three shots off the lead at 6-under, while world No. 1 Brooks Koepka finished 1-under.
Tiger Woods struggled Thursday, finishing at 4-over par, and acknowledged afterward he "went the wrong way."
A storm prevented the public from watching until 10 a.m. ET, almost three hours after the round started.
