CHICAGO – Jason Day continued his march to try and claim the world number one ranking, stretching his lead to six shots after the third round of the BMW Championship on Saturday. The 27-year-old Australian remained on course for a wire-to-wire victory as he fired a two-under 69 to reach 20-under 193 in the third of four tournaments in the USPGA Tour's FedEx Cup playoffs. Day has a six-shot cushion over Americans Scott Piercy (67) and Daniel Berger (70) who are tied for second at the Conway Farms Golf Club. World number one Rory McIlroy birdied three of the last four holes for a four-under 67 and is in sole possession of fourth, seven shots back of Day. Day wobbled down the stretch, making two of his four bogeys on the back nine after making just two in the first two rounds.