Marc Leishman carded an impressive 64 at Firestone to earn the lead after the first round of the WGC-Bridgestone Invitational.
The Australian quickly found form with his putter in Ohio on Thursday, recording eight birdies on his way to reaching the top of the leaderboard on six-under-par.
Major winners Justin Rose and Charl Schwartzel are just one shot behind Leishman, with Ryan Moore joining the pair in returning a 65 to move into a tie for second.
Rickie Fowler is among a group of players on three-under after 18 holes, while Tiger Woods managed to recover from a number of errors to end the day just one stroke further back.
Open champion Rory McIlroy, who can become world number one again with a victory, is currently on one-under alongside the man currently in possession of top spot, Adam Scott.