Tony Finau produced a blistering 6-under-par 64 on Thursday to take the early lead at the Charles Schwab Challenge in Fort Worth, Texas, with local favorite Jordan Spieth lurking close behind.
Spieth and Canada's Roger Sloan share second place, one stroke back, after each shot 65 at Colonial Country Club.
Tied for fourth is a cluster of nine players at 3 under, including Jason Dufner and Jimmy Walker. Mexico's Abraham Ancer is among eight others at 2 under.
Finau reached 2 under with birdies at Nos. 3 and 4, and after a hiccup bogey at the fifth, he tacked on two more birdies at Nos. 7 and 8. He then strung together three in a row beginning at No. 11, sinking putts of 24 and 27 feet at the 12th and 13th, respectively, to get to 6 under before parring the final five holes.
The breakthrough for Finau -- after he struggled to a final-round 79 at last week's PGA Championship -- coincided with a switch to a claw grip on his putter, something he said he's considered for a while.
"It's something that I've kind of been thinking," Finau told PGA.com afterward. "It's an itch I wanted to scratch. ... To me, it was just perfect time. ... If I feel like something is better, I'm not afraid to change, no matter the results."
In addition to his long makes on the back nine, Finau holed birdie putts of 20 feet (No. 3) and 19 feet (No. 7) on the front nine, as well as a par putt of 20 feet at the 16th.
"I wanted to try something different, and it felt great out there today," he said.
Like Finau, Spieth's putter was red hot, as the Dallas native drained birdie putts of 30 and 46 feet and didn't miss inside 15 feet all day. He sank a 73-foot chip shot for a birdie at No. 13.
"It's nice to see some results off what I believe is the progress I've been making," Spieth said afterward, per the Dallas Morning News. "At the same time, it's one round. I've got to keep my head down and keep working."
Spieth, the 2016 winner of the event, racked up eight birdies in the round, overcoming a double bogey at the par-4 18th when he found water with his approach shot. After he started on the back nine, the double bogey dropped him from 4 under to 2 under, but he birdied four more on the front, including No. 9 after a bogey at the eighth.
Sloan notched three birdies on each side, with the only blemish a bogey at No. 9.
Defending champion Justin Rose of England is tied for 95th among 121 players after shooting 74.
--Field Level Media