Aug. 28 (UPI) -- Rory McIlroy and Patrick Cantlay were tied atop the leaderboard after Friday's second round of the BMW Championship at Olympia Fields Country Club in Olympia Fields, Ill.
McIlroy ended the day at 1-under 139 to share the 36-hole lead with Cantlay, who had a 2-under 68 in the second round to climb 13 spots. McIlroy had a 1-under 69, as the course at Olympia Fields continued to challenge players.
"I think the test is what's helped me focus and concentrate because if you lose focus out there for one second ... just one lapse in concentration can really cost you around here," McIlroy said. "I think one of the big keys this week is just not making big numbers.
"If you hit it out of position, get it back in position, make sure that your worst score is bogey and move on. Honestly, bogeys aren't that bad out here."
McIlroy and Cantlay are one shot ahead of Hideki Matsuyama and Dustin Johnson entering the weekend. Matsuyama -- the only player to reach 4-under par at any point this week -- held the lead after the first round but had four bogeys over his final 10 holes for a 73. Johnson finished with two straight birdies for a 69.
Adam Scott, Brendon Todd, Louis Oosthuizen, Billy Horschel and Tony Finau were at 1-over par and tied for fifth after the second round. Mackenzie Hughes, Kevin Kisner and Bubba Watson were a shot back of that group at 2-over 142.
Meanwhile, Tiger Woods' PGA Tour season appears to be two rounds from concluding. He had to sink a 35-foot par putt on his last hole to shoot 75, which left him nine strokes behind the lead.
Woods, who needs to finish around fourth to have any chance of competing at the season-ending Tour Championship next week in Atlanta, is tied for 55th at 8-over 148 going into the weekend.
The third round of the BMW Championship runs from noon to 6 p.m. EDT Saturday. The top 30 from the tournament move on to the Tour Championship next week at East Lake in Atlanta for a chance at its $15 million prize.