Phil Mickelson birdied his last four holes to take a commanding six-shot lead into the final round of the Phoenix Open as the Australians struggled to make an impact in Arizona. American Mickelson struck seven birdies in a blemish-free 64 third round to sit on an imposing 24 under total, well clear of countryman Brandt Snedeker who occupies outright second on 18 under. Greg Chalmers leads the Aussie contingent, the veteran left-hander climbing 18 places into a tie for 20th after a five-under 66 took him to 11 under the card. Compatriot Aaron Baddeley carded six bogeys in his 73 to slide down to 64th on four under, and Jason Day sits a shot further back following a one-over 72. Mickelson rolled in two birdies on the front nine before taking charge late on at TPC Scottsdale. He added another birdie at the par-five 13th before breaking par from holes 15 to 18 to stretch his lead and tie the tournament&aposs lowest 54-hole mark, set by Mark Calcavecchia in 2001. Snedeker also avoided any bogeys in his six-under 65 but the FedEx Cup champion never looked like reeling in the unwavering leader. Irishman Padraig Harrington carded the lowest score of the day, an eight-under 63, to share third place with American Ryan Moore on 16 under, while another local, Troy Matteson, occupies sole fifth a shot back. Brendan Steele climbed 14 spots on the back of his third-round 65 and shares sixth spot with American compatriot Bill Haas on 14 under. Scott Piercy, Brendon de Jong, Gary Woodland and Roberto Castro rounded out the top 10 on 13 under overall.