The inaugural 3M Open saw a player post a 9-under-par 62 score for the second day in a row, with Bryson DeChambeau riding his hot round Friday to the lead at the tournament's midway point in Blaine, Minn.
The 62 at TPC Twin Cities marked the lowest round of DeChambeau's career. Coupled with his first-round 66, he sits at 14-under 128, two shots ahead of Canada's Adam Hadwin.
Scott Piercy, who fired a 62 on Thursday, followed up with a 1-under 70, leaving him tied for third at 10 under with Sam Saunders (4 under on Friday), Brian Harman (4 under) and Sam Burns (5 under).
Saunders is the grandson of Arnold Palmer, who designed TPC Twin Cities.
Scott Brown (6 under on Friday), Kevin Streelman (6 under), India's Arjun Atwal (3 under) and Australia's Curtis Luck (6 under) share seventh place at 9 under. Atwal gained a place in the event through a Monday qualifying tournament.
DeChambeau opened on the back nine and made the turn in 3 under. Then he heated up on the front nine, registering six birdies from Nos. 1-8 before capping his bogey-free round with a par.
He missed only one green in regulation and was solid with the putter, even if he wouldn't discuss why.
"That's secret stuff, man," he said of his putting in a post-round interview. "I'm not talking to you about that."
DeChambeau added, "My main focus is driving it as well as I have. I mean, if I can keep doing that, the putts are going to drop. Some are going to miss. ... You're not going to be perfect, but if I can keep driving it well just like I have been, and become more and more confident, that's the Bryson we saw last year."
Brooks Koepka, the world's top-ranked player, shot a 1-over 72 on Friday, leaving him at 3 under -- the last score that made the cut. He is tied for 70th place.
Phil Mickelson missed the cut for the fourth time in his past six starts, shooting 74-73-147. Nate Lashley, who earned his first career victory last week in Detroit, missed the cut after carding 69-73-142.