Washington - US Open champion Dustin Johnson birdied the final hole to cap a four-under-par 66 and grab a share of the first-round lead alongside Hideki Matsuyama and Kevin Chappell at the USPGA Tour Championship in Atlanta, Georgia, on Thursday.
World number two Johnson arrived at East Lake Golf Club for the $8.5 million season finale atop the FedExCup playoff standings after his victory in the penultimate playoff event, the BMW Championship, two weeks ago.
The $10 million bonus on offer to the playoff series winner was still clearly in the 32-year-old's sights after a round of five birdies and one bogey.
"I know there's a lot on the line, but there's a lot on the line every week," said Johnson, who was four-under through 12 to join the leading group, bogeyed 13 but regained a share of the lead at the par-five 18th.
"I come out with the same mentality. Today I felt really relaxed out there all day," added Johnson, who opened with a birdie from a bunker at the first hole and finished with a birdie at the last, where he belted his approach shot to 58 feet and made a four-footer for birdie. "I felt like I had good mojo going all day and swung it very nicely."
With three victories this season, including his first major title and a WGC trophy at the Bridgestone Invitational, Johnson is also the frontrunner in the US tour's player of the year race.
Japan's Matsuyama rode a hot putter to his 66. The 24-year-old known as one of the best ball-strikers in the game struggled with his irons, hitting just 11 greens in regulation.
"My putting and short game saved me today," Matsuyama said. "I wasn't hitting the ball real crisp."
Chappell, in contrast, hit 16 greens in regulation, making all four of his birdies on the front nine and coming home in even par to maintain his place atop the leader board.
The leading trio were one stroke in front of a group led by world No 1 Jason Day of Australia, who had four birdies and one bogey in a 67 that left him tied with South Korea's Kim Si-Woo and American Kevin Kisner.
Day, who pulled out of the BMW Championship with a bad back, is seeking his first title in four months.
Last year's FedExCup champion Jordan Spieth was in a quartet a further stroke back on 68 that also included Northern Ireland's Rory McIlroy, England's Paul Casey and US Ryder Cup hopeful Justin Thomas.
Spieth roared back from his bogey-double bogey start, holing out from a bunker for birdie at 13 and rolling in two 20-foot birdie putts to cap his round.
McIlroy's rollercoaster of a round included an opening bogey, three birdies from the third through fifth holes, back-to-back double-bogeys at seven and eight and four straight birdies from 12 through 15.
McIlroy had birdie chances at 16 and 17 before he had to lay up at the par-five finishing hole.
He started the day ranked sixth in the FedExCup standings, and in with a chance of taking home the playoff prize with a victory - and some help from the top five players who can claim the big payday outright with a victory.
Those five are Johnson, Patrick Reed, Adam Scott, Day and Casey.
Reed opened with a disappointing 73, while Scott opened with a 69.
First-round scores on Thursday in the $8.5 million US PGA Tour Championship, final event in the FedExCup playoffs at East Lake in Atlanta, Georgia (USA unless noted, par-70):
66 - Hideki Matsuyama (JPN), Kevin Chappell, Dustin Johnson
67 - Kevin Kisner, Kim Si-Woo (KOR), Jason Day (AUS)
68 - Justin Thomas, Jordan Spieth, Paul Casey (ENG), Rory McIlroy (NIR)
69 - Matt Kuchar, Adam Scott (AUS)
70 - Jhonattan Vegas (VEN), Ryan Moore
72 - Bubba Watson, Gary Woodland, Brandt Snedeker
73 - Jason Dufner, J.B. Holmes, Roberto Castro, Emiliano Grillo (ARG), Russell Knox (SCO), Patrick Reed
74 - Charl Schwartzel (RSA), Sean O'Hair, Daniel Berger, Phil Mickelson, Jimmy Walker
77 - William McGirt, Kevin Na