Gary Woodland went on a stunning back-nine birdie blitz to open up a one-shot lead after the first round of the US PGA Championship at Bellerive Country Club.
Rickie Fowler had set the target at five under in the morning and it looked like he would carry the lead into day two as the chasing pack got close but then fell back as the afternoon wore on.
At one over after seven holes, Woodland looked an unlikely challenger, but he birdied seven of his last 11 holes to sign for a six under par 64 and edge ahead of his fellow American.
South African Brandon Stone was then at four under alongside two-time Major Championship winner Zach Johnson, a shot clear of a group of 11 players including World Number One Dustin Johnson, World Number Three Justin Rose, 2015 champion Jason Day, American Pat Perez, Belgian Thomas Pieters and England's Ian Poulter.
Woodland has never had a top ten in 29 Major appearances but he does have three US PGA Tour titles to his name - including this season's Waste Management Phoenix Open.
The 34 year old bogeyed the first after finding sand but an excellent pitch into the eighth and a 15-footer on the ninth saw him turn in red numbers.
He holed a 44-foot left-to-righter on the 11th and the putter stayed hot, with efforts of over 20 feet on the 12th and 16th sandwiching a wonderful approach into the 14th and handing him a share of the lead.
He then played the par five 17th in textbook fashion to take the outright lead for the first time in a Major.
Woodland was born and studied in neighbouring Kansas and while he admitted that brought some good-natured heckling from the Missouri crowd, it also allowed him to have a big local following.
"I probably pressed a little bit too much early," he said. "I've been hitting the golf ball beautifully coming into this week.
I'm just happy and excited to be as close to home as I'll ever be - Gary Woodland
"I have a million friends and family out here which is pretty cool but I was probably off pressing a little bit and I settled in there really on five and outside of that I hit the golf ball beautifully.
"I'm just happy and excited to be as close to home as I'll ever be."
Fowler finished second at the Masters Tournament earlier this year for this third top two finish in a Major, as he continues his search for an elusive victory in one of golf's big four events.
The 29 year old birdied the 14th but gave the shot back on the 16th before bouncing back on the par five next to turn in 34.
A 15-footer on the first and an excellent tee-shot on the third had him in a share of the lead and he pulled away late in the round, holing a 30-footer from the fringe on the seventh before capitalising on the par five eighth.
Many of the players in the field were wearing yellow ribbons in tribute to Jarrod Lyle who sadly passed away on Wednesday after losing his long battle with cancer.
Fowler went a step further, donning a yellow shirt in honour of the Australian, and he admitted that Lyle had been in everybody's thoughts on Thursday.
"We've all been thinking about Jarrod a lot," he said. "I was scripted to wear dark blue today, that definitely immediately changed last night.
"You also think about it as far as Jarrod wouldn't want us out here feeling sorry for him or feeling bad or anything. He'd probably come out here and kick us in the butt and tell us to man up and go have some fun.
"So it's a little bit kind of bittersweet. You're trying to go out there and keep living life like he did, but it's unfortunate that he's not here with us."
We've all been thinking about Jarrod a lot. Jarrod wouldn't want us out here feeling sorry for him or feeling bad or anything - Rickie Fowler
Stone has a Rolex Series victory to his name at the Aberdeen Standard Investments Scottish Open and two other European Tour wins but had missed the cut in both pf his previous US PGA Championship appearances.
A long putt on the first got him off to the perfect start and he also took advantage of the eighth before hitting a stunning appraoch into the 14th.
A bogey on the 15th threatened to derail the 25 year old but he holed a 30-foot left-to-righter on the 16th and then made a putt from the fringe on the next.
Zach Johnson made four birdies in five holes from the eighth to surge up the leaderboard but could not make any further progress, needing a birdie on the last to get back to four under.
Former Open champion Stewart Cink was in the group three shots off the lead alongside fellow Americans Austin Cook, Brian Gay, Kevin Kisner and Ollie Schniederjans.