Dustin Johnson double bogeyed the last to sit second and two strokes behind leader Chesson Hadley after the second day at the Palmetto Championship in South Carolina on Friday.
Play was suspended late on Friday due to inclement weather but world number one Johnson finished his round with a three-under 68 to remain firmly in contention after his opening day 65 at Congaree Golf Club.
Johnson shot four birdies in six holes on his back nine, grabbing a share of the lead with Hadley, before dropping two on the 18th.
The American started strongly on Friday, birdieing his opening two holes, and appeared in ominous form, driving within 20 feet on the 344-yard par four 15th.
Johnson had been part of a four-man pack tied for second following the opening day, along with 33-year-old Hadley who carded a five-under 66 on Friday, backing up his 65 on Thursday.
Hadley, who had missed five straight cuts entering the Palmetto Championship, bogeyed the second but responded with four birdies from his next five holes.
"I definitely didn't see this coming," Hadley said. "I missed all those cuts in a row, and thank goodness I had three weeks off just to kind of hit the reset switch, get out on the boat, and just kind of forget about some things and spend some time with some family."
The unheralded American leads with 11-under, two strokes ahead of Johnson, with Tain Lee in third at eight-under.
The weather prevented Lee from finishing his second round, getting through 16 at four-under.
American Pat Perez and Irishman Seamus Power both carded five-under 66s to move up the leaderboard into a share of fourth spot. They join Harris English, Chez Reavie and Erik van Rooyen in equal fourth at six-under.
Overnight leader Wes Roach had a nightmare second day, starting with four bogeys from his first five holes, to finish with a six-over 77 to slide way down the leaderboard.
Brooks Koepka shot a second-round 73 to sit three-over and appears likely to miss the cut, which is not yet confirmed given play was suspended.
For Nana. @ChessonHadley wants his putter to be sweet and kind to him so he named it after his late grandmother.— PGA TOUR (@PGATOUR) June 11, 2021
He currently holds a 3-shot lead and ranks 1st in SG: Putting this week. pic.twitter.com/rIsbKekvgf