Tiger Woods rolled back the years with a round of 65 as he opened up a two-shot lead at the halfway mark of the WGC-Cadillac Championship. Woods, a six-time winner of the event, was in a five-way share of the lead at the start of play on Friday but pulled clear thanks to a brilliant seven-under par second round. The American world number two sunk eight birdies and just the solitary bogey as he reached 13 under overall at TPC Blue Monster in Doral, Florida. Fellow overnight leader Graeme McDowell is in second position after carding a 67 to move to 11 under. The Northern Irishman is the only player to avoid bogey at the event and remains within touching distance of Woods, while there were signs of improvement from compatriot Rory McIlroy. World number one McIlroy endured a difficult opening round but produced a confidence-boosting 69, his first sub-par round of the season, to sit on two under. American duo Phil Mickelson and Steve Stricker are three shots off the pace following rounds of 67. Another local, Bubba Watson, and Swede Fredrik Jacobson are four strokes behind Woods after both carded 69s. South African Charl Schwartzel hit a seven-under 65 round to be joint-seventh alongside American Keegan Bradley, who produced a four-under 68. American Dustin Johnson improved to ninth on the leaderboard after his round of 69 left him on seven under overall. John Huth (67) leads an 11-way tie for 10th position, a logjam that includes the likes of Swede Peter Hanson and Spaniard Sergio Garcia.