Sungjae Im, who missed two straight cuts upon his return from a wrist injury, has found form in the Valspar Championship where he holds the opening-round lead.
Im made two eagles that offset a few late mistakes in his round of seven-under 64 for a one-shot lead over Brandt Snedeker.
The Copperhead course at Innisbrook was the third straight stop on the Florida swing where the conditions were firm and the greens already getting that yellow sheen. Im was up to the task by giving himself ample birdie chances and converting six of them.
He also holed eagle putts of 18 feet on the par-5 11th and 35 feet on the par-5 first after making the turn. Only a pair of bogeys over the last four holes slowed him.
The surprise was the 45-year-old Snedeker, the US captain for the Presidents Cup, who received a sponsor exemption. He had a bogey-free round at Innisbrook for the first time in 14 years, running off three straight birdies to start the back nine in his round of 65.
Snedeker,, who hasn't won in eight years and had only two top 10s in the last year, switched to a mallet putter a few weeks ago and is starting to see some putts go in.
He started with a 20-foot birdie on No.1 and had a 45-foot birdie putt drop on No.12.
"Had a really good game plan - just relied on my putter," said Snedeker.
"I putted great today, made a bunch of footage of putts, and put myself in position off the tee, hit a lot of fairways and greens and made it stress-free which was nice."
Snedeker led the field in putting and made nearly 150 feet of putts, which included a pair of par putts from just outside 10 feet.
Davis Thompson was at 66, with Billy Horschel among those at 67. Horschel, who missed The Players Championship last week, is running out of time to either win or get back inside the top 50 to qualify for the Masters.
Riviera winner Jacob Bridgeman also had a bogey-free round. He was at 68 along with another bogey-free effort, this one from Xander Schauffele.
Australian rising star Karl Vilips shot 69 and is tied 17th.
Vilips made three birdies with his only blemish coming on the par-five 5th where he made bogey.
Also at 69 was Jordan Spieth, who had reason to expect more.
Spieth looked as though he might catch Im even while playing in tougher, gusting conditions in the afternoon. He was five under on the front nine and had a four-foot birdie putt on the par-5 11th.
But he missed that, missed a 3 1/2-foot par putt on the 13th and dropped three shots over the three-hole stretch known as "Snake Pit," including a double bogey on the 16th by driving into the water.