Irishman Padraig Harrington fired a 10-under par 61, the lowest score of his career, to seize the clubhouse lead on Thursday in round one of the US PGA Transitions Championship.
Harrington's bogey-free round set a course record on the Copperhead layout at Innisbrook and included a 75-foot putt for birdie at the par-3 17th hole, the longest putt he has made in a US PGA event.
"I would like to tell you it was funneling right up the green and couldn't go anywhere else, but certainly the last 15 feet it was right in the middle of the hole," Harrington said. "That's a bonus, obviously."
Harrington's previous low round had been a 62, fired three times, most recently at the 2009 Portugal Masters.
The old course record was also a 62, fired by Jeff Sluman in 2004 and matched by fellow American Mark Calcavecchia in 2007.
"I'm very comfortable where my game is at," Harrington said. "I've made a lot of good improvements and I feel like things are ready to happen. Obviously today it showed the potential. Today is a peak.
"We will wait and see what happens over the next number of weeks. I'm trying to stay patient. I know my game is good. One of the hardest things is to wait with confidence."
Harrington's prior longest US PGA putt was just under 66 feet on his way to winning the 2005 Barclays Classic.
Three-time major winner Harrington, who has not won any event since the 2010 Johor Open on the Asian Tour, closed his round with three birdies, the last a 15-footer at the par-4 18th.
Harrington opened with back-to-back birdies, birdied the par-3 fourth and the par-4 seventh, then had back-to-back birdies to close the front nine and begin the back side, adding yet another at the par-4 12th.
A struggle to make par at the par-5 11th took the brief thoughts of matching the all-time tour low of 59 out of Harrington's head.
"On 11 I choked like a dog on," he said. "I had an 8-footer up the hill, as easy a putt as you could get and I got over it and started thinking, if I hole this, I'm 7-under par, seven holes to go. I just got totally out of where I should have been, hit a bad putt and missed.
"But if anything, it kind of got the 59 out of my head."
Harrington's last victory US tour triumph came at the 2008 PGA Championship. His other major triumphs came at the 2007 and 2008 British Opens.