David Lingmerth carded his second successive five under par 65 to take a two-shot lead into the halfway point of the Quicken Loans National at TPC Potomac at Avenel Farm
The Maryland venue holds happy memories for the Swede, who won an event on the developmental Web.com Tour five years ago, and he is in firm contention to claim his second title here and on the PGA Tour.
Lingmerth, whose only win on the PGA Tour came two years ago at the Memorial Tournament, regularly found the fairway while his impressive putting helped him make five birdies in a blemish-free second round.
Ireland's Seamus Power carded a round of 69 to leave him one over and safely in for the weekend, with the cut at four over.
Afterwards's Lingmerth told the PGA Tour's official website: "Any time you come back to a course where you have great memories, it's always going to help. It was a good feeling to show back up.
"I do think it's a course that is visually straightforward, it's easy to pick good targets. Of course I probably have a bit of an advantage having played and won here but it's just a great golf course, so I'm happy to be here.
"I've been in pretty good control of my game so far but there's still 36 holes to go, so I'm looking forward to the weekend. Everything's feeling really good and I'm pleased with where I'm at."
Putts from 15 and 25 feet gave Lingmerth birdies at the second and third while he picked up a third shot in four holes by sinking an 18-footer on the fifth.
An excellent up and down from a greenside bunker gave him his fourth birdie of the day and he ended his round in style as a fine approach on the last gave him a regulation putt that lifted him to 10 under overall.
Geoff Ogilvy is the nearest challenger after matching Lingmerth's score on Friday. The Australian, the 2006 US Open champion and former world number three, had six birdies and one bogey on the 15th - his sixth hole.
America's Daniel Summerhays is two shots further back on six under after a 68, while India's Arjun Atwal and Sung Kang of South Korea are snapping at his heels, five shots behind Lingmerth.
