The always calculating Bryson DeChambeau fired a 9-under 62 in Round 2 of the 3M Open, helped largely by improved putting.
But he's not going to reveal the tweaks he made.
"The thing that's kind of changed, I'm not really going to tell," DeChambeau said after his round Friday. "It's a little secret."
DeChambeau ended his day with a four-shot lead at TPC Twin Cities and is on track to top his T8 finish at the Travelers two weeks ago for his best result of the season.
"(My putting has) been through a lot of practice, trial and error, and a lot of struggle too," the 25-year-old said. "People don't realize that you know, I won a lot last year and obviously struggled a little bit, but they don't realize that struggle is always what is going to make me better."
The 3M Open leader has yet to make a bogey through 36 holes and made more than 137 feet of putts in Round 2. He's looking to claim his 6th PGA Tour title.