Miami - Two-time major winner Martin Kaymer was hot on the heels of rookie co-leaders Cody Gribble and Wesley Bryan Thursday after one round of the PGA Tour's Honda Classic.
Bryan and Gribble both teed off early at PGA National in Palm Beach Gardens, Florida, and produced six-under par 64s that none of the later starters could match.
But Gribble and Bryan, who is coming off a career-best tie for fourth at Riviera Country Club on Sunday, have no margin for error with Germany's Kaymer and India's Anirban Lahiri just a stroke back, with seven more players on 66.
Kaymer finished with back-to-back birdies for his 65, chipping in from the green-side rough at 17.
"It was just one of those shots you want to get within three feet or so," Kaymer said. "It was a bit of a bonus. You try to get away with a par and then chip in for two. I take it. Sometimes it works out the other way and you make a bogey."
Lahiri drained a 25-foot eagle putt at the 18th to join Kaymer at five-under.
Bryan and Gribble had set the target early.
Bryan played his first eight holes at even par before a birdie at 18, then poured in five birdies in his last nine holes.
He was happy to be back at PGA National, where he won his card for the Web.com Tour just over a year ago - going on to win three times on the developmental circuit to earn his PGA Tour card.
"A place that I'm comfortable at, and a golf course I know, they are few and far between out here," Bryan said. "It's my first run at all these tournaments out here. I love this place, love this golf course and I had a great day."
Gribble, who lifted his first PGA Tour title in October with a storming finish in the Sanderson Farms Championship, hit all 18 greens in regulation to seize his share of the lead.
He offset his only bogey at the par-four 16th with seven birdies, including at his last two holes.
Leading scores after Thursday's opening round of the PGA Tour's Honda Classic at par-70 PGA National (USA unless noted):
64 - Cody Gribble, Wesley Bryan
65 - Martin Kaymer (GER), Anirban Lahiri (IND)
66 - Ben Crane, Graham DeLaet (CAN), Sean O'Hair, C.T. Pan (TPE), Rickie Fowler, Ryan Palmer, Ian Poulter (ENG)
67 - Ryan Blaum, Scott Stallings, Jhonattan Vegas (VEN), Jim Herman, Brian Harman, Kelly Kraft, Brandon Hagy, Jon Curran, Noh Seung-Yul (KOR), Marc Leishman (AUS), Blayne Barber, Joey Garber
68 - Francesco Molinari (ITA), Tyrone Van Aswegen (RSA), Emiliano Grillo (ARG), Tyrrell Hatton (ENG), Sergio Garcia (ESP), Zach Johnson, Paul Casey (ENG), Brian Gay, Adam Scott (AUS), Russell Henley, Rafa Cabrera Bello (ESP), Morgan Hoffmann, Luke List, Billy Hurley, Brian Stuard, John Peterson, Seamus Power (IRL), J.J. Spaun