KOHLER, 14 Aug 2015, (AFP) - The Swede got as low as eight-under, and his 36-hole total of seven-under 137 gave him the outright lead when he walked off the course.
But Lingmerth's prediction that he'd be caught proved true, and Australians Jason Day and Matt Jones were both at nine-under on the course when thunderstorms swept across Whistling Straits on Friday evening, halting play for the day.
England's Justin Rose was eight-under with one hole to play when the horn sounded, while Americans Harris English and Tony Finau were both at seven-under.
Organizers said the round would resume at 7 am (12:00 GMT) on Saturday. It was a fittingly chaotic end to a day that saw five players briefly hold at least a share of the lead.
"Obviously, I opened my big mouth to the boys playing with us, I said, 'The end is in sight, and 30 seconds later they blew the horn,'" Rose quipped. "So my name is mud all over here."
Despite the hassle of returning to finish, Day wasn't disappointed that the round was stopped.
"I was kind of glad that we're in," he said. "Obviously it's a mess out there, and so I'm just trying to get some rest tonight and go into tomorrow."
Spieth, who started the day five off Dustin Johnson's lead at six-under, had six birdies and one bogey.
After victories in the Masters and US Open, the 22-year-old Texan has a chance to join Ben Hogan and Tiger Woods as the only men to win three major championships in the same year.
After teeing off on 10, Spieth birdied 11 and bogeyed 12. A birdie at 16 was followed by an improbable birdie at 18, where he holed out from a bunker.
"All in all, I felt like I scored the way I played," said Spieth, who was less than satisfied with his driver.
"My ball striking into greens is pretty good. I made a couple of putts today. With a couple of chip-ins for the week and really smart course management and good speed control, we have been able to hold ourselves in there."
With Rory McIlroy's world number one ranking in his sights, Spieth separated himself from the Northern Ireland star.
McIlroy posted a second successive 71 on Friday that left him five shots off the pace in his bid for a second straight PGA Championship crown.
His round was marred by a double bogey at the par-four 18th, where a beautiful drive was followed by a second shot into the rough.
He got back on track with his own unlikely break -- an eagle at the par-five second hole where he chipped in from the front of the green.
But McIlroy played the remaining holes in even par, unable to keep pace as Spieth picked up three birdies on his inward run.
"I didn't putt as well as I would have liked," McIlroy said. "It would be great to hole a few more putts, because I feel like I'm giving myself plenty of chances."
British Open champion Zach Johnson, the third player in the "super-group" along with Spieth and McIlroy, endured another frustrating day that had him headed for an early exit.
He opened with three straight birdies, but finished with four birdies and four bogeys in a 72 that left him three-over for the tournament and outside the projected cut line.
"It wasn't very good," he said.
A hot, humid morning saw plenty of birdies on the par-72, 7,501-yard Straits course hugging the shores of Lake Michigan.
Japan's Hiroshi Iwata matched a major championship record with a nine-under par 63 -- the 27th time a player has shot 63 in a major. Two players -- Greg Norman and Vijay Singh -- did it twice.
Iwata had eight birdies and an eagle with one bogey to build a four-under total of 140 for 36 holes.
Former world number one Tiger Woods, however, wasn't making any headway.
The 14-time major champion was one-over through 13 holes and looking set to miss the cut at a third stright major.
Partial scores on Friday in the weather-disrupted second round of the PGA Championship at Whistling Straits (play halted by storms, round to resume Saturday):
137 - David Lingmerth (SWE) 67-70
138 - Scott Piercy (USA) 68-70, Jordan Spieth (USA) 71-67, Brendan Steele (USA) 69-69
139 - George Coetzee (RSA) 74-65
140 - Marcel Siem (GER) 70-70, Billy Horschel (USA) 72-68, Hiroshi Iwata (JPN) 77-63, Charles Howell (USA) 70-70, Matt Kuchar (USA) 68-72
141 - Kevin Chappell (USA) 73-68
142 - Brooks Koepka (USA) 73-69, Webb Simpson (USA) 71-71, Cameron Smith (AUS) 74-68, Justin Thomas (USA) 72-70, Rory McIlroy (NIR) 71-71, Yang Yong-Eun (KOR) 70-72, Luke Donald (ENG) 72-70, Henrik Stenson (SWE) 76-66, Charl Schwartzel (RSA) 73-69
143 - Steve Stricker (USA) 71-72, Brendon De Jonge 72-71, Emiliano Grillo (ARG) 70-73, Sean O'Hair (USA) 75-68, Bae Sang-Moon (KOR) 71-72
144 - Kiradech Aphibarnrat (THA) 72-72, Danny Willett (ENG) 74-70, Troy Merritt (USA) 74-70, Patrick Reed (USA) 75-69, Kevin Streelman (USA) 73-71, Brian Gaffney (USA) 71-73, Chesson Hadley (USA) 73-71, Thomas Bjorn (DEN) 69-75
145 - Phil Mickelson (USA) 72-73, Jason Bohn (USA) 74-71, Boo Weekley (USA) 75-70
146 - Nick Watney (USA) 78-68, Koumei Oda (JPN) 79-67, Jason Dufner (USA) 71-75, Nick Taylor (CAN) 73-73, Victor Dubuisson (FRA) 76-70
147 - Zach Johnson (USA) 75-72, John Senden (AUS) 71-76, Shaun Micheel (USA) 74-73, Marc Leishman (AUS) 79-68, Shane Lowry (IRL) 78-69, Kevin Kisner (USA) 75-72, Bernd Wiesberger (AUT) 72-75, Padraig Harrington (IRL) 76-71, David Hearn (CAN) 76-71, Rory Sabbatini (RSA) 71-76
148 - Richie Ramsay (SCO) 81-67, Graeme McDowell (NIR) 73-75, Daniel Berger (USA) 74-74, Kevin Na (USA) 74-74, George McNeill (USA) 71-77, Jimmy Walker (USA) 75-73, Rafael Cabrera-Bello (ESP) 73-75, Russell Knox (SCO) 77-71, Tim Clark (RSA) 75-73
149 - Shawn Stefani (USA) 74-75, Tommy Fleetwood (ENG) 77-72, Steven Bowditch (AUS) 74-75, Graeme McDowell (NIR) 73-76
150 - Soren Kjeldsen (DEN) 72-78, Andy Sullivan (ENG) 78-72, Miguel Angel Jimenez (ESP) 76-74, Ian Poulter (ENG) 75-75, Camilo Villegas (COL) 75-75
151 - Chris Wood (ENG) 76-75, Adam Scott (AUS) 76-75, Bob Sowards (USA) 75-76, Pablo Larrazabal (ESP) 79-72
152 - Ben Polland (USA) 76-76, Joost Luiten (NED) 80-72, Davis Love (USA) 79-73, Cameron Tringale (USA) 78-74
153 - Ben Martin (USA) 76-77, Alexander Levy (FRA) 77-76, Brett Jones (AUS) 75-78, Eddie Pepperell (ENG) 78-75
154 - Rich Beem (USA) 76-78
159 - Omar Uresti (USA) 77-82, Darren Clarke (NIR) 78-81, Charles Frost (USA) 76-83
160 - Sean Dougherty (USA) 79-81
165 - Daniel Venezio (USA) 89-76
169 - Alan Morin (USA) 87-82, Ryan Kennedy (USA) 79-90