Padraig Harrington managed the lowest score of his career so far as he posted a course record 61, ten-under-par, at the Transitions Championship in Florida.
The Dubliner has recently dropped to number 90 in the world rankings but showed the form that brought him three Major titles in 2007 and 2008.
Harrington carded seven birdies inside the first 12 holes and added a further three on each of the final three holes.
Harrington’s nearest challenger is the unheralded American Will Claxton on seven under.
“Where do I start,” he said after today’s round. “I've been playing nicely in practice. I play better on the Monday, Tuesday, Wednesday than I do on the Thursday, Friday, Saturday, Sunday.
"I'm trying to stay patient. I know my game is good. One of the hardest things is to wait with confidence. A lot of my good weeks are struggling just to get inside the Top 10 and that's kind of just showing up in my world rankings, because unless you're finishing first, second or third you are not getting substantial points in that sense.
“So, yeah, it's been a strange last year, but as I said, I'm very comfortable where my game is at. I've made a lot of good improvements and I'm feeling like things are ready to happen."
Harrington's last victory came in the Iskandar Johor Open on the Asian Tour in 2010.