Rory McIlroy in share of the lead through two rounds in Chicago

Rory McIlroy hits his tee shot on the ninth hole during the second round of the BMW Championship golf tournament. Picture: Charles Rex Arbogast/AP

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.

McIlroy 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.