Rory McIlroy is one of just two players to finish under par at the BMW Championship on Friday as the world’s best golfers found themselves at the mercy of the gruelling Olympia Fields course.
The Northern Irishman carded a one-under 69 to take a share of the lead alongside American Patrick Cantlay, who also sits at one-under through two rounds thanks to Friday's score of two-under 68.
McIlroy, who has managed just one top 12 finish since the PGA Tour resumed in June, handled the fast and firm course better than many of his peers as he refused to let a few wayward shots get the better of him.
After picking up a few quick birdies to start the round, the 31-year-old found himself in trouble on the par-four 14th when he overshot the green.
However a sensational chip shot minimised the damage, McIlroy settling for a bogey before bouncing back with another birdie on the 16th.
Despite some mixed results on the front nine, in which he picked up three more bogeys alongside two birdies, McIlroy was able to stay composed enough to secure pole position heading into what is sure to be a tough weekend.
“As it got later in the day, the golf course definitely became a little firmer, a little tougher,” said the world number four.
“The wind got up a little bit. A little disappointed to drop those shots on the way in, but I think if you shoot anything under par on this golf course, you’ve got to be pretty pleased.”
Dustin Johnson and Hideki Matsuyama finished the day at even to lead a clogged chasing pack, with 29 players sitting within five shots of the leaders.
Johnson, who is leading the season-long FedExCup standings, pumped his fist after he drained a tricky 32-foot birdie putt on his last hole.
Tiger Woods’ poor putting led to a miserable round that included five bogeys, a double bogey and two birdies for a round of five-over 75. The 15-time major champion is currently eight-over 148 for the tournament and would need a miraculous turnaround to make the Tour Championship.
Collated second round scores and totals (USA unless stated, par 70):
139 Rory McIlroy (Irl) 70 69, Patrick Cantlay 71 68
140 Dustin Johnson 71 69, Hideki Matsuyama (Jpn) 67 73
141 Tony Finau 70 71, Adam Scott (Aus) 72 69, Brendon Todd 73 68, Louis Oosthuizen (Rsa) 72 69, Billy Horschel 70 71
142 Bubba Watson 72 70, Mackenzie Hughes (Can) 69 73, Kevin Kisner 72 70
143 Matthew Wolff 72 71, Xander Schauffele 73 70, Alex Noren (Swe) 72 71, Lanto Griffin 70 73, Brendan Steele 72 71, Joaquin Niemann (Chi) 72 71, Russell Henley 74 69, Tyrrell Hatton (Eng) 73 70, Bryson DeChambeau 73 70, Jim Herman 71 72
144 Carlos Ortiz (Mex) 70 74, Abraham Ancer (Mex) 70 74, Harry Higgs 70 74, Viktor Hovland (Nor) 71 73, Tyler Duncan 68 76, Patrick Reed 73 71, Tom Hoge 71 73
145 Jason Kokrak 74 71, Gary Woodland 75 70, Brian Harman 72 73, Danny Lee (Nzl) 73 72, Michael Thompson 72 73, Paul Casey (Eng) 73 72, Sebastian Munoz (Col) 70 75, Corey Conners (Can) 76 69, Matthew Fitzpatrick (Eng) 70 75
146 Kevin Na 72 74, Richy Werenski 74 72, Max Homa 74 72, Jon Rahm (Spa) 75 71, Adam Hadwin (Can) 74 72, Harris English 75 71
147 Robby Shelton 75 72, Mark Hubbard 70 77, Byeong-Hun An (Kor) 73 74, Nick Taylor (Can) 75 72, Daniel Berger 73 74, Justin Thomas 73 74, Maverick McNealy 77 70, Scottie Scheffler 75 72, Ryan Palmer 71 76, Dylan Frittelli (Rsa) 72 75
148 Joel Dahmen 71 77, Cameron Smith (Aus) 75 73, Tiger Woods 73 75
149 JT Poston 72 77, Adam Long 72 77, Collin Morikawa 76 73
150 Jason Day (Aus) 76 74, Charles Howell III 75 75
151 Matt Kuchar 75 76, Sungjae Im (Kor) 77 74, Cameron Champ 77 74
152 Andrew Landry 77 75
155 Talor Gooch 76 79
156 Kevin Streelman 76 80
158 Marc Leishman (Aus) 80 78