Australians Jason Day and Matt Jones were tied at the top of the PGA Championship standings when play in the second round was abandoned for the day.
The pair had progressed to nine-under-par, one clear of Justin Rose, when an afternoon storm brought play to a halt, with Day having completed 14 holes of his second round, while Jones was through 12 holes.
One of the day's early starters, world number two Jordan Spieth powered up the leaderboard with a six-under 67 to move into contention for his third major title of the year.
World number one Rory McIlroy made it back-to-back 71s as he hovered seven strokes back on two-under, while Tiger Woods looked set to miss the cut after stumbling to four-over after 13 holes, with the cut projected at two-over.
Having begun the day three shots back of overnight leader Dustin Johnson, Day began strongly with birdies at the second, fifth and sixth holes before dropping a shot at the par-four ninth to take the turn in 34. Three birdies in three holes from the 11th to the 13th saw the Queensland native roar up the leaderboard before play was suspended with Day on the 15th hole.
Jones, who like Day carded an opening 68, began on the 10th tee, and soon rattled off three straight birdies on the 11th, 12th and 13th holes. Further birdies followed at the 18th and third holes before the 35-year-old's charge was halted by the bad weather with six holes still to play.
Rose is next best on eight-under, with the Englishman five-under for the day with one hole to play after an eventful round that included eight birdies, a bogey, and a double bogey at the par-four sixth.
Sweden's David Lingmerth began the day one shot back from first round leader Dustin Johnson and carded an eventful two-under par 70 which included eight birdies, four bogeys and a double-bogey to set the pace in the clubhouse. Lingmerth is joined on seven-under by Harris English (68) and Tony Finau (71).
But it's a man a further shot back who really got people talking.
Playing alongside McIlroy, Spieth showed the world's top-ranked player a thing or two in a top quality round of 68 that sees him in with a shout of yet another major success.
Starting at the tenth tee, Spieth birdied the 11th before giving that stroke right back at the 12th. It would prove his lone blemish of the day, while he added further birdies at the 16th and 18th to take the turn in 34.
On his closing nine, Spieth added birdies on the first, third and sixth holes to finish on five-under for the day and six-under overall.
While Spieth was superb, McIlroy struggled to get going, with an eagle at the par-five second, two birdies and a double-bogey at the 18th – his ninth hole – the Ulsterman's scoring on the day.
First round leader Johnson found the going considerable harder on Friday. After registering two birdies and a bogey on the front nine, Johnson birdied the 10th before slumping to three bogeys in four holes before play was called off with the American on the 15th.
Former world number one Woods struggled yet again. The day began brightly for Woods with birdies at the second and third holes, but a double-bogey six at the par-four sixth hole brought him crashing back to earth. A bogey at the eighth followed before a string of pars followed to ensure no further damage was inflicted by the time play was suspended.
Woods was not the only former major winner to struggle on Friday, with John Daly finding the water three times on his way to a 10 at the par-three seventh. The American would end the day with an 82.
Hiroshi Iwata of Japan produced the low round of the day, with a record-tying 63, just a shot shy of the what would have been the best round in the tournament's history. Iwata made the most of good conditions early on to notch up eight birdies, an eagle at the par-five 11th and a lone bogey at the ninth to move to four-under after opening with a 77.