Wyndham Clark shot a five-under-par 67 to take a two-stroke lead in a wind-hit first round of the Arnold Palmer Invitational.
Shane Lowry is among a group of players tied for second after a 69, one better than Rory McIlroy and Justin Rose on a day when only 14 players broke par at Bay Hill.
Two late birdies lifted former US Open champion Clark to the top of the leaderboard. Lowry shared the lead on four-under-par after an eagle at the 16th, but he dropped a shot at the last.
He is tied with American Ryder Cup captain Keegan Bradley, Canadian Corey Conners and Christiaan Bezuidenhout of South Africa.
McIlroy also bogeyed the last, having dropped a stroke on the opening hole. In between, he carded six birdies and two more bogeys en route to a 70.
Rose joined him at two-under-par late in the day, despite also opening with a bogey and adding a double bogey six at the ninth.
South Korea’s Si Woo Kim, Australian Cam Davis and American Max Greyserman also shot 70s, one better than world number one Scottie Scheffler.
He was joined at one-under-par by fellow Americans Collin Morikawa, Justin Thomas and Patrick Cantlay.
Xander Schauffeler suffered on his return from a rib injury, an opening 77 threatening his run of making 57 consecutive cuts.
“(I’m) a bit of a masochist, I guess,” Schauffele said. “I knew I was going to come in on short notice to what is sort of like a major championship set-up around the greens, and with the greens being crusty, I really felt it there more than anything else.”