New York - Troy Merritt matched the Liberty National course record with a nine-under par 62 to grab a one-stroke lead after Thursday's opening round of the US PGA Northern Trust tournament.
On a day when Masters champion Tiger Woods struggled to a 75 and shared 116th among 120 starters, it was 33-year-old American Merritt who stole the show with a bogey-free day.
"That putter was hot today and the greens were rolling beautifully and (I) just took advantage of it," Merritt said.
World number two Dustin Johnson was one stroke back with Kevin Kisner and Spain's Jon Rahm sharing third on 64. Third-ranked Rory McIlroy, world number four Justin Rose, Webb Simpson and Tony Finau were on 65.
Merritt equaled the record at the Jersey City, New Jersey, layout set by compatriot Kevin Chappell in the third round of the 2013 Northern Trust.
He also boosted his chances of moving on in the US PGA playoffs, with only the top 70 in season points advancing from this playoff opener to next week's second event at Medinah, where only the top 30 in season points will qualify for the season-ending Tour Championship in Atlanta in two weeks.
Merritt entered this week 72nd in points, two outside the field to move on, but as the only player outside the top 30 among the eight leaders, he will leap to fourth in points if he can win the title.
"This week it's a little bit different with just trying to get into next week," Merritt said. "Now we can shift our focus from winning the golf tournament."
Merritt began on the back nine, sinking birdie putts from 22 feet at the par-3 11th and 19 feet at the par-4 12th, then two more from inside 10 feet for a run of four consecutive birdies.
Merritt also birdied 17 and sank a 12-footer for birdie at the first to keep his momentum, then ran off three birdies in a row starting with a 13-footer at the par-3 fourth and with an approach inches from the cup at 14.
A title would be the third of Merritt's career after the 2015 National and last year's Barbasol Championship. He settled for second two weeks ago at the Barracuda Championship.
It was a year ago that Merritt had a blood clot removed from his left arm and it was in January that he had a rib removed to prevent thoracic outlet syndrome, a compression of blood vessels that led to the clot.
For fifth-ranked Woods, meanwhile, it was a day of misery battling back stiffness in only his fifth start since winning the Masters in April.
The 43-year-old, twice a runner-up at Liberty National, had three birdies, five bogeys and a double bogey after a morning start.
Woods, a 15-time major champion whose 81 career PGA titles are one shy of Sam Snead's all-time record, admitted his frustration, saying his back was a bit stiff and his game was not quite right.
"It was just off. I was just trying to feel it, trying to find it, and then could never get it," Woods said.
"I had my opportunities to turn it around and I didn't do it. I just didn't play well. I just didn't hit any good shots and didn't make any putts."
Woods, who won last year's Tour Championship, ranks 28th in season points, but is likely to miss the cut Friday and fall out of the top 30.
That means he will go to next week's BMW Championship at Medinah needing to overtake rivals merely to earn a chance at defending his title in the season finale at East Lake.
Leading scores after Thursday's opening round of the US PGA Northern Trust tournament in Jersey City, New Jersey (par-71, USA unless noted):
62 - Troy Merritt
63 - Dustin Johnson
64 - Kevin Kisner, Jon Rahm (ESP)
65 - Tony Finau, Webb Simpson, Rory McIlroy (NIR), Justin Rose (ENG)
66 - Patrick Reed, Max Homa, Chez Reavie, Danny Willett (ENG), Brian Stuard, Chesson Hadley, Corey Conners (CAN), Russell Knox (SCO), Patton Kizzire
67 - Adam Schenk, Kiradech Aphibarnrat (THA), Adam Hadwin (CAN), JT Poston, Wyndham Clark, Harold Varner, Carlos Ortiz (MEX), Cameron Smith (AUS), Jordan Spieth, Abraham Ancer (MEX), Joel Dahmen, Justin Thomas, Kang Sung (KOR), Im Sung-jae (KOR), Matt Jones (AUS)