Leaderboard: -7 P Casey (Eng) -5 N Watney (US), G Willis (US), M Laird (Sco), S Stallings (US) Selected others: -3 M Kaymer (Ger)
Casey went round the Copperhead course without making a bogey
England's Paul Casey fired a seven-under-par 64 to grab a two-stroke lead in the first round of the Transitions Championship at Innisbrook, Florida.
The world number seven shot a bogey-free round to lead Americans Nick Watney, Garret Willis and Scott Stallings, and Scotland's Martin Laird.
World number one Martin Kaymer of Germany finished on three under.
"I got lucky, got a few good bounces and made some putts," said Casey, who finished with back-to-back birdies.
"I'm very happy with that round. The nice thing was we had some favourable wind. It was great golfing weather. I didn't even see the fog this morning."
Watney, who headed into this tournament on the back of the biggest win of his career at the World Golf Championship in Miami last weekend, also had seven birdies but dropped two shots over his final six holes.
Play was suspended because of darkness with three players still on the course and they will return early on Friday to complete their first rounds.