CHERRY HILLS VILLAGE, September 5, 2014 (AFP) - Four-time major winner McIlroy rolled in four birdies in a five-hole stretch around the turn at the $8 million PGA Tour event at the Cherry Hills Country Club course.
"It's tricky. We've had a couple of days to adjust to the altitude, so that's fine, but these greens have gotten so much firmer over the last 24 to 48 hours," McIlroy said.
US Open champion Martin Kaymer is one of nine players tied at two under. He stands alongside Spain's Sergio Garcia, Canada's Graham DeLaet, Matt Every, Billy Horschel, Kevin Chappell, Russell Henley and Chesson Hadley.
Sweden's Henrik Stenson is also two-under par and was on the 18th hole when play was suspended. He and the others will finish their rounds early Friday. Stenson was one of nine players still on the course when the horn sounded.
World number one McIlroy is aiming for his fourth win of 2014 which includes major titles at the Open Championship and the PGA Championship.
McIlroy started on the back nine and after a pair of pars, he dropped his tee shot inside five feet at the par-three 12th and drained that for birdie.
He two-putted for birdie at the par-five 17th and parred number 18 as he made the turn at three under.
McIlroy surged to the top of the leaderboard on the front nine. He got up and down for birdie on the par-four first and followed with a 14-foot birdie putt on the second. He made it three in a row with a four-footer for birdie on number three.
He made bogey on two of his final three holes to finish at three-under. He admitted he is not happy with the ending.
- 'Worked out pretty good' -
"I am a little frustrated coming off the course because I feel like it should have been better than what I finished," McIlroy, of Northern Ireland, said. "I just try to play a little bit more of feel and it seemed to work out pretty good."
The 21-year-old Spieth rolled in a 22-foot birdie on number six and followed with a short birdie putt at the seventh to gain a share of the lead. Spieth parred the last two holes to post three-under.
"I really like the golf course. It's nice to be back and to see the golf course and understand that this is one of the very few events where I may have more experience than a lot of guys," said Spieth, who played the Cherry Hills course as an amateur.
Justin Rose, who won this event two years ago, shot a one-under 69. He was joined there by Erik Compton, South Korea's K.J. Choi, Charles Howell, Ryan Palmer, Chris Stroud, and Hideki Matsuyama of Japan.
Jerry Kelly and 2008 champion Camilo Villegas are also one-under par, but have two holes and one hole remaining in their opening round.
Leading scores on Thursday after the first round of the PGA Tour's BMW Championship. Play halted because of darkness with nine players still on the course (par 70, USA unless noted):
67 - Rory McIlroy (NIR), Gary Woodland, Jordan Spieth
68 - Sergio Garcia (ESP), Martin Kaymer (GER), Graham DeLaet (CAN), Matt Every, Billy Horschel, Kevin Chappell, Russell Henley, Chesson Hadley
69 - K.J. Choi (KOR), Charles Howell, Justin Rose (ENG), Erik Compton, Ryan Palmer, Chris Stroud, Hideki Matsuyama (JPN)
70 - Jim Furyk, Phil Mickelson, Ernie Els (RSA), Bubba Watson, Jason Day (AUS), Seung-Yul Noh (KOR), Cameron Tringale