Shane Lowry hit an opening-round 70 at the Honda Classic, where Kurt Kitayama posted the lowest score of the day with a six-under par 64 at PGA National Resort in Palm Beach Gardens, Florida.
Offaly man Lowry split his two birdies and bogeys between the front and back nine to sit half a dozen shots off the lead, with Padraig Harrington a further three shots back after a 73.
The three-time major winner came a cropper at the ninth with a double bogey and struggled on the back nine with three bogeys before finishing well with a birdie at the last.
World No 289 Kitayama [above] missed the cut in his past five starts, but that didn't stop him from excelling at a challenging track. He leads Daniel Berger, Chris Kirk and Rory Sabbatini by one shot.
Tied for fifth at three under are Peter Uihlein, Andrew Kozan, Aaron Rai, Danny Willett and Matthias Schwab.
World No 289 Kitayama started on the back nine and birdied his first three holes, then recovered from a lone bogey by stringing together four more birdies at holes three to six, the last a 21-foot putt from just off the green.
The 29-year-old has three worldwide wins in Europe and Asia but none on the PGA Tour.
Berger compiled five birdies, four on the front nine, during a bogey-free round. The Florida native is one of the highest-ranked players [No 21] in the Honda field.
Kirk had a wild ride with eight birdies and three bogeys, while the 45-year-old Sabbatini matched Berger by avoiding bogey at PGA National for the first time in his career.
Tied for fifth on three-under are Peter Uihlein, Andrew Kozan, Englishmen AaronRai and Danny Willett and Austria's Matthias Schwab.
