Fourth-ranked Cameron Young rode a hot start and surged to a five-stroke lead after Friday's second round of the PGA Cadillac Championship.
Young birdied four of the first seven holes on his way to firing a five-under par 67 and stand on 13-under 131 after 36 holes at Trump National Doral in Florida.
"I've just putted really well," Young said. "I've left myself in mostly doable spots when I've missed greens.
"But I haven't driven it great and that's something I hopefully look to return to normal over the next couple days."
Three-time major winner Jordan Spieth, fellow American Alex Smalley and Canada's Nick Taylor shared second on 136 with American Gary Woodland on 137.
Young, who won the Players Championship in March and captured his first PGA title last August at Greensboro, said he feels comfortable with a big lead, well aware it could vanish quickly on the weekend.
"I've been around the lead quite a bit and I'm not particularly uncomfortable. I've liked this golf course thus far," Young said.
"There's a lot of guys four or five back. I'm sure somebody will be four- or five-under tomorrow so you have to prepare for that."
Young topped putting and scrambling statistics.
"I avoided the bad misses for the most part. It's not like I drove it awful but I would love to play from the fairway a couple more times the next couple days," he said.
"There's a lot of golf to be played on a difficult golf course but so far I've played well. If I can drive it a little bit better, I feel like I can keep cruising and see what happens."
Young reached the green in two and birdied the par-five first hole to grab the solo lead then stretched the margin with a 17-foot birdie putt at the third and a 27-foot birdie putt at the fifth.
The lead reached four strokes when Young sank a seven-foot birdie putt at the seventh.
Young's approach at the par-five eighth was plugged in a bunker. He punched out into an adjacent bunker then blasted to five feet and rescued par.
At the par-three ninth, Young missed the green but rolled the ball just outside six feet and saved par again.
Young sank a 16-foot birdie putt at the par-three 13th, boosting his advantage to five, but then needed two shots to escape greenside rough at 14 and made his first bogey of the tournament.
Young drove the green at the par-four 16th and two-putted for birdie from 26 feet to restore his five-stroke margin.
'PICK YOUR SPOTS'
World No 1 Scottie Scheffler, a four-time major winner, fired a 67 to join a pack in sixth on 138.
"It's a golf course where there's some trouble – there's a fair amount of water but the greens are fairly big. Fairways aren't too narrow but they are hard to hit just based on how firm the golf course is," Scheffler said.
"There's definitely some challenge out there. You have to pick your spots. I did a good job of giving myself some looks today. Wish I had holed a few more but overall if I do that over the course of the next couple days I'll be in a good spot."
The $20 million signature event marks the PGA Tour's return to the Blue Monster course for the first time since 2016. Doral had hosted a LIV Golf event in recent years.