Potomac - Sweden's David Lingmerth clung to a one-stroke lead over American Daniel Summerhays when threatening weather halted play during Saturday's third round of the US PGA National.
Lingmerth, seeking his second PGA title after taking the 2015 Memorial, stood on eight under par for the event but two-over for the day at TPC Potomac, a renovated layout hosting its first PGA event since 2006.
Severe thunderstorms approached the par-70 layout with 36 of 74 players to make the cut still on the course.
Summerhays, seeking his first US tour crown as well, birdied the par-four fifth to seize second on seven-under, one stroke ahead of South Korean Kang Sung and 2006 US Open champion Geoff Ogilvy of Australia, with India's Arjun Atwal fifth on five-under.
Lingmerth, who began the day two strokes ahead of Ogilvy, opened with a bogey after bunkering his approach but birdied the par-five second after dropping his third shot four feet from the cup.
The Swede pitched out of a bunker to save par from five feet at the par-three third and stay on 10-under but Ogilvy missed a 10-foot par putt and fell three back.
But Lingmerth, who won a 2012 developmental tour event on this course, found water off the fourth tee and made double bogey, trimming his edge to one stroke.
Summerhays, third in last year's PGA Championship, made a 13-foot birdie putt at the par-four fifth to move within one of the leader before Ogilvy stumbled again with a bogey at the fifth.
Kang charged into contention with birdie putts from beyond 15 feet at the fifth and sixth holes.
Four British Open berths are available to the top unqualified finishers for the July 20-23 showdown at Royal Birkdale. Only one of the top 17 so far is already qualified.
Ogilvy, 40, seeks his ninth US PGA victory and 13th professional win overall. His most recent title came in 2014 at Reno, Nevada.
Atwal, a 44-year-old whose 2010 Greensboro triumph made him the first India-born US PGA tour winner, is playing only his fifth event of the year.
Kang, 30, seeks his first PGA title, having led after 54 holes at Houston in April only to finish second.
Ninth-ranked American Rickie Fowler fired a 68 to share the clubhouse lead on level-par 210, eight strokes off the pace.
"I feel like I've got a low one in me," Fowler said. "Got back into a decent position to at least give it a run tomorrow (Sunday)."