Roberto Castro has shot a course record-equalling round of 63 to earn a three-shot lead on day one of the Players Championship at TPC Sawgrass.
The American holed an eagle and seven additional birdies in Florida on Thursday to give him an overall score of nine-under-par in what is his first appearance at the tournament.
Rory McIlroy also enjoyed the opening round as six birdies put the Northern Irishman on six-under with American Zach Johnson.
Tiger Woods is one of six players, including Hunter Mahan and Webb Simpson, who are a shot further back. Padraig Harrington and Sergio Garcia are both on four-under with four others.
However, defending champion Matt Kuchar struggled during the opening round, with two bogeys on the final four holes leaving him eight shots off the pace.