Brendon Todd used a red-hot putter to grab a two-shot lead over Rickie Fowler in the second round at the WGC-FedEx St Jude Invitational in Memphis.
World number 51 Todd, who won two PGA Tour titles on consecutive starts last November, carded a bogey-free, five-under-par 65 at TPC Southwind for an 11-under halfway total.
The 35-year-old American, who converted an impressive 50-foot birdie putt over a slope at the par-three 14th, walked off the course feeling better than ever heading into the weekend.
Open champion Shane Lowry remains best of the Irish. The Offaly man's round of 69 contained three birdies and two bogeys and left him on three-under-par.
Four-time major winner Rory McIlroy fared much better today, carding a four-under-par round of 66, which took him to one-under.
Graeme McDowell’s level-par 70 left him one shot ahead of McIlroy.
"In my whole life, this is definitely the most confident I've ever felt with my golf game. It's probably the most versatile I've ever been ball-striking-wise," said Todd.
"I still don't hit it far, but I feel like I'm able to shape shots a little bit. And my short game's solid, so it just kind of comes down to how the putting is."
Brooks Koepka, who led by two shots after the first round, started on the back nine and reached the turn at two under for the round but made double-bogey at the par-four second where his tee shot found a fairway bunker and then needed three putts from 57 feet.
The four-times major winner, who struggled in his last three events, said his putter let him down on Friday but that he was not going to lose sleep with plenty of golf still to play.
"I felt like I did everything we were trying to do, just wasn't working, wasn't seeing the line," said Koepka, who will defend his PGA Championship title next week.
"Even yesterday I said I didn't feel quite comfortable over anything inside five feet and today it just felt kind of the same.
"I've got 36 holes to go, man, I ain't worried."
Elsewhere, a flawless, six-under-par round propelled Danielle Kang to an early lead at the LPGA's inaugural Drive On Championship in Toledo, Ohio, with South Africa's Lee-Anne Pace one stroke behind.
The 54-hole tournament at Inverness Club started on Friday in a fanless setting as the LPGA got back into action after the coronavirus outbreak forced the suspension of play following the Women's Australia Open on 16 February.
Americans Maia Schechter and Amy Olson were tied for third at three-under along with New Zealand's Lydia Ko and world number eight Minjee Lee of Australia.
World number four Kang, who won the Women's PGA Championship in 2017, put up six birdies and told reporters she was happy to be back in competition after not working with her caddie for six months.
"I would say I just didn't have any hiccups on any part of the game," said the 27-year-old.
"I definitely miss-hit some shots, miss-hit some putts, but I had some great iron shots, great tee shots, and great putts and chips.
"So any time one part of my game kind of gave he me a tough shot, I made it up with a good save."