Philadelphia - Tiger Woods fired his lowest opening round in nearly 20 years to join Northern Ireland's Rory McIlroy at the top of the leaderboard at the BMW Championship on Thursday.
The 14-time major winner Woods and McIlroy have a one-stroke lead after both shot eight-under 62 which marked the American's best PGA first round since the 1999 Byron Nelson Classic.
Woods managed an eagle and seven birdies and his only hiccup being a late bogey on his back nine at the Aronimink Golf Course in Philadelphia.
Woods was joined in the lead by McIlroy who highlighted his round of 10 birdies with a career-best six in succession, beginning with the last hole of his front nine.
McIlroy though let slip any thoughts of a 59 when he bogeyed his 16th and 17th holes of the round.
This is the first time Woods has shared a PGA Tour lead after any round since capturing the 2013 WGC-Cadillac Championship.
Woods and McIlroy had played a nine-hole practice round together on Tuesday.
"I made a few putts today and also from right out of the gate with birdies at 10 and 12 and 13 so that was a nice way to get things rolling," said Woods, who started on the back nine.
Woods had ignited thoughts of his career first 59 after an outward nine that produced a seventh hole eagle and four birdies in a six-under par 29.
It is the sixth occasion in Woods' career he's recorded nine holes in 29 or better, and on four of those five prior occasions he has gone on to win.
Woods moved to seven-under par with a birdie at his 10th hole. He then parred his next five holes ahead of a 16th hole birdie before his only bogey at his 17th. He also birdied 18.
"I made some great putts out there today including getting off to a better start than I have most of the season," he said.
"To shoot 29 on the front nine helps. It helped a lot."
Woods clearly looked refreshed after electing not to visit the course on Wednesday. He also skipped the Pro-Am due to the heatwave conditions.
"The heat is hard for me because I lose so much weight out here," said Woods. "I lose strength and I lose power and endurance."
McIlroy had been a shot clear of Woods at nine-under par after 15 holes when Woods headed for the clubhouse.
McIlroy pared his 15th but three-putted for bogey both his seventh and eighth holes before a consolation birdie at the last.
"What was worst was just not giving myself a better chance to shoot the 59," he said.
"I can accept a bogey on a hole like on the eighth (17th) hole and the bogey on seven wasn't good, but you don't get many opportunities to break 60 and today was one of them and I didn't capitalize."
American Xander Schauffele, who hopes to secure the last spot on the USA Ryder Cup team, is in third place with a 63, while Rickie Fowler, who played alongside Woods, returned from injury to shoot a 65.
Scores from opening round of the US PGA Tour's BMW Championship at Aronimink Golf Club near Philadelphia on Thursday (par-70; USA unless stated):
62 - Tiger Woods, Rory McIlroy (NIR)
63 - Xander Schauffele
64 - Billy Horschel, Peter Uihlien, Justin Thomas, Alex Noren(SWE)
65 - Ryan Armour, An Byeong-hun (KOR), Rickie Fowler, Aaron Wise
66 - Hideki Matsuyama (JPN), Jon Rahm (ESP), Justin Rose (ENG), Brian Gay, Henrik Stenson (SWE), Webb Simpson, Keegan Bradley
67 - Jordan Spieth, Bryson DeChambeau, Jason Day (AUS)
68 - Ian Poulter (ENG), Tony Finau
69 - Patrick Reed, Brooks Koepka, Paul Casey (ENG), Tyrrell Hatton (ENG)
70 - Dustin Johnson, Francesco Molinari (ITA)
71 - Tommy Fleetwood (ENG), Bubba Watson
73 - Phil Mickelson
74 - Adam Scott (AUS), Marc Leishman (AUS)