England's Brian Davis brought himself firmly into contention at the Greenbrier Classic in Sulphur Springs, West Virginia with a best-of-the-day six under par 64.
The Londoner was one over par after a first round that included a double bogey at the par four 16th but he bounced back in style, carding seven birdies against one bogey to sit joint fourth on five under, two shots behind leaders Brendon de Jonge and Webb Simpson.
Starting his round on the tenth tee, Davis turned at one under but then claimed birdies on the first, third, fifth, seventh and ninth.
Davis has not yet won on the US PGA Tour, though he came agonisingly close in last year's Heritage Classic when he called a two-stroke penalty on himself on the first hole of a play-off, handing the title to Jim Furyk.
If he is to go one better here he will have to overhaul De Jonge and Simpson as well as overnight leader Trevor Immelman.
De Jonge of Zimbabwe was three under for the day and American Simpson two under to lead on seven under par overall, while South Africa's Immelman was level par for his round and sat one stroke behind them.
De Jonge, aiming for his first US PGA title, said: "The last couple of years I've had a couple of stretches where I've played well for an extended period of time.
"I'm playing nicely coming in this week, so, hopefully I keep it going."
There were some notable names who did not make the cut, including Phil Mickelson and defending champion Stuart Appleby.
Appleby shot a 59 to win last year, but could only manage a 72 to finish three over par - the same mark as Mickelson and two outside the cut of one over.