Australian duo Matt Jones and Jason Day moved to the top of the leaderboard at the US PGA Championship as Justin Rose also moved into contention before storms ended play early on day two at Whistling Straits.
Swede David Lingmerth had set the clubhouse target at seven under after following up his opening 67 with a 70 on Friday morning but Jones, who was among the late starters, made five birdies in 12 holes to move to nine under.
Day, who has finished in the top ten in six of the last 11 Major Championships, had also started on four under and picked up birdies on the second, fifth and sixth before making a bogey on the ninth.
Consecutive birdies from the 11th to the 13th then catapulted him into the lead and he was on the 15th when the hooter sounded at 1728 local time due to storms.
"I'm glad that we are in," Day said. "It can get a little dangerous out there. It's a good idea to come back in the morning."
The second round will get back under way at 0700 on Saturday with round three beginning 30 minutes after it is completed.
Rose made a double bogey on the fourth but only dropped one more shot alongside eight birdies and he was on the 18th tee when the players were brought off.
The 2013 US Open champion admitted it was going to be "a bit of a drag" to face an 0500 alarm call for the scheduled restart, but joked: "I opened my big mouth to the boys I was playing with and said the end was in sight. Thirty seconds later they blew the horn, so my name was mud walking up the 18th."
Overnight leader Dustin Johnson had been eight under par after a beautiful putt of nearly 30 feet on the tenth but bogeys on the 11th, 13th and 14th saw him fall away from the leaders.
Earlier in the day, Hiroshi Iwata had become just the 25th man to fire a record-equalling low round of 63 at a Major, breaking the course record at Whistling Straits in the process, but all eyes were on Jordan Spieth whose 67 moved him to six under.
The Masters Tournament and US Open champion, who is attempting to become just the third player after Ben Hogan and Tiger Woods to win three Majors in a season, birdied the 11th but failed to get up and down from a greenside bunker on the 12th before picking up a shot on the 16th and chipping in on the 18th. He then holed from 12 feet for another birdie on the first.
Spieth made another birdie on the par three third after putting his tee shot to within five feet and a sixth birdie of the day at the sixth put the American right in the mix going into the weekend.
"It was definitely gettable today," he said. "I got off to a good start making birdie on my second hole, and then the one on 18 was a great spark to get things going, get a little confidence, a little pep in my step.
"I was staring one over on the round down and instead make the turn in two under. So that was a nice kind of two-shot swing in one shot.
"Then I was able to take advantage on the front."
It was a good morning for low scoring with George Coetzee firing an impressive 65 to sit two off the clubhouse lead and 2013 Race to Dubai winner Henrik Stenson shooting 66 to alleviate any danger he may have had of missing the cut - which looked likely to fall at one or two over par.
World Number One and defending champion Rory McIlroy recorded a 71 to sit seven shots off Jones and Day's lead and admitted he was "a little bit annoyed" at failing to take advantage of perfect conditions.
Playing his first tournament since the US Open in June after seven weeks out due to an ankle ligament injury, McIlroy made amends for a double bogey on the 18th by chipping in for eagle on the second and also carded two birdies and one bogey.
"I felt like tee to green I hit the ball pretty well, I'm probably just not as sharp with the short game as I would like to be," he said. "It was good to get the two shots back that I dropped on 18 and I gave myself good chances on the third and fifth, but did not take them.
"There's plenty of chances out there and if I can convert a few hopefully there is a low score in me.
"I felt like I played better than what the score reflected. A little bit annoyed. I felt like I should have got that ball up and down on seven and then I had a great chance on eight for birdie and didn't take that. A couple of days in a row where I haven't finished the round of golf the way I wanted to.
"I don't know if it's rust or I just didn't putt well, so maybe just work on that a little bit before I tee off tomorrow and it would be great to hole a few more putts, because I feel like I'm giving myself plenty of chances."
Stenson's six under round got him to two under for the tournament after an opening 76 and the Swede, who had eight birdies in his first 15 holes, would have gone even lower had he not had back to back bogeys at seven and eight.
"I didn't score well yesterday," he said. "I played all right, actually, I played a whole lot better than what the score showed and then it was just tougher conditions in the afternoon.
"It was, I guess, a good two shot swing from playing in the morning to the afternoon. And that certainly didn't help when I was not scoring the way I should.
"So, yeah, at least good to see that I can get a good round in on this golf course, because I haven't managed that in the past and hopefully we've got another couple in us."
Marcel Siem fired a second consecutive 70 to sit at four under and Y E Yang, Brooks Koepka and Luke Donald were all alongside McIlroy and Stenson at two under.
Emiliano Grillo was one under for the tournament and heading for the weekend in his first Major despite a one over 73 while Danny Willett recovered from an opening 74 with a 70 to sit level.
