Zach Johnson tames difficult course to lead the World Challenge THOUSAND OAKS, Calif., Dec. 5 (UPI) -- Zach Johnson warmed up on the back nine Thursday and shot a 5-under 67 that gave him the lead after one round of the Northwestern Mutual World Challenge. Johnson birdied five of the first seven holes on the back side of the Sherwood Country Club course and although he bogeyed the final hole he walked away with a one-shot lead over Matt Kuchar. The exhibition event brings together 18 of the top players in the world. Just five members of the elite field broke par on a course that presented more of a challenge than usual. Johnson and Kuchar were the only players to finish under 70. Hunter Mahan and Bubba Watson both turned in a 2-under 70 and Tiger Woods shot a 71 to stand alone in fifth place. Woods is a five-time winner of the tournament. Graeme McDowell and Jim Furyk each had a 72. Johnson, who has been the runner-up in the tournament twice, birdied the first two holes and made the turn in 1-under. He then birdied the 10th, 11th, 13th, 14th and 16th holes. Three of those are par-5s.