Potomac - Sweden's David Lingmerth stumbled to a three-over par 73 on Saturday but clung to a one-stroke lead over American Daniel Summerhays after the third round of the US PGA National.
Lingmerth had two birdies, three bogeys and a double bogey over the 7,107-yard TPC Potomac layout to stand on seven-under 203 after 54 holes.
"Long, hard fought day for me and here I am," Lingmerth said. "I'm still right where I need to be for tomorrow and I'm not too worried about the way I played today. I think I can come back tomorrow better."
Lingmerth, seeking his second PGA title after taking the 2015 Memorial, won a 2012 developmental tour event on this course, hosting its first PGA event since 2006. And he's chasing his first wire-to-wire victory.
"It's a situation I haven't previously been in," Lingmerth said. "I haven't had the wire-to-wire scenario in my career, but a lot of great players have won tournaments that way and I would like to do it as well. I'm feeling like I'm up for the challenge. I think it's a great opportunity."
Summerhays shot 70 to stand second with compatriot Spencer Levin firing the day's low round, 65, to reach third on 205, one stroke ahead of South Korea's Kang Sung and Australians Geoff Ogilvy and Curtis Luck.
Severe thunderstorms caused a 91-minute delay and together with afternoon heat provided tougher conditions for the leaders.
Lingmerth opened with a bogey but birdied the par-five second after dropping his third shot four feet from the cup. He then found water off the fourth tee and made double bogey, trimming his edge to one shot.
"Got off to a bit of a rough start," said Lingmerth. "Missed a couple tee shots to the left, which is something I don't usually do, and it maybe got me a little unnerved with tee balls for the rest of the day because I didn't hit as many fairways as I usually do.
"I managed somehow to miss in decent spots where I was able to scramble pretty good."
Lingmerth began the back nine with a bogey, taking five shots to reach the green after finding rough, native grass and a bunker.
"Definitely a different way of playing it," Lingmerth said.
He answered with a birdie at the 299-yard par-4 14th, nearly driving the green and leaving his second shot inches from the cup.
But Lingmerth, who began the tournament with back-to-back 65s, made bogey at the par-3 17th, finding a bunker off the tee and missing a five-foot par putt.
"I'm not worried about the way I played today," Lingmerth said. "I think I can go out there tomorrow and shoot another 65."
Summerhays, third in last year's PGA Championship, made a 13-foot birdie putt at the fifth but made bogey at 11, hitting the cart path well right off the tee.
Levin, the world number 369 who hasn't managed a top-10 finish in more than a year, birdied three of the last six holes to move into contention for his first PGA victory, making six birdies in all.
"My putter was hot," he said. "I was really happy with the way I rolled it."
Levin could claim one of four spots on offer in the British Open later this month at Royal Birkdale.
"Securing a spot for the Open, if I can do that, that would be awesome," Lingmerth said.
Top scores after Saturday's second round of the US PGA National (par-70, USA unless noted):
203 - David Lingmerth (SWE) 65-65-73
204 - Daniel Summerhays 66-68-70
205 - Spencer Levin 70-70-65
206 - Curtis Luck (AUS) 68-71-67, Kang Sung (KOR) 66-69-71, Geoff Ogilvy (AUS) 67-65-74
207 - Kyle Stanley 70-70-67, Charles Howell 71-69-67
208 - Martin Laird (SCO) 67-72-69, Andrew Loupe 70-69-69, Johnson Wagner 66-71-71
209 - Kevin Streelman 68-72-69, Keegan Bradley 71-68-70, Michael Kim 69-69-71, Ricky Barnes 68-68-73, Harris English 70-67-72, Nick Taylor (CAN) 66-70-73
210 - Patrick Rodgers 71-73-66, An Byeong-Hun (KOR) 70-74-66, Jason Gore 69-74-67, Rickie Fowler 70-72-68, Brian Gay 70-71-69, Zac Blair 67-74-69, Seamus Power (IRL) 72-69-69, Bill Haas 69-70-71, Marc Leishman (AUS) 66-72-72, Kyle Reifers 70-68-72, Danny Lee (NZL) 70-68-72, Arjun Atwal (IND) 68-67-75