Phil Mickelson joined Vijay Singh atop of the BMW Championship leaderboard on the back of an eight-under 64 performance, while Australia&aposs Adam Scott is firmly in the mix. Mickelson, a four-time Major winner, sunk 10 birdies to surge 12 positions up the table and move to 16-under at the end of the third round. The American is level with overnight leader Singh after the Fijian bogeyed the 18th and final hole in Indiana. Singh ended the day with a three-under 69, which included seven birdies and four bogeys. England s Lee Westwood and Northern Irishman Rory McIlroy are a shot behind and tied for third heading into the fourth and final round. Westwood birdied three of his final four holes to register a four-under 68, while world number one McIlroy managed a three-under 69. Scott is two shots adrift and right in the mix for his first title of the season. The British Open runner-up, who began the day in 13th, shot a six-under 66 and carded seven birdies to move 14-under overall. “I played well again today, and obviously to have any chance to contend tomorrow I had to make some sort of a move, and it all kind of came together around the turn, and I played fairly solid,” Scott said. “I putted nicely today for the first time in a couple weeks.” Scott sits alongside American&aposs Robert Garrigus (66) and Dustin Johnson (67) in a tie for fifth. Fellow Australian Greg Chalmers (68) is in a share of 43rd, while Geoff Ogilvy (74) is a shot back. John Senden (76) and Marc Leishman (71) are further down the leaderboard. Tiger Woods, a two-time winner of the event after it was renamed in 2007, is three shots behind Mickelson and Singh after managing a one-under 71 on Saturday. Zach Johnson (68), Graeme McDowell (69) and Bo Van Pelt (71) share ninth spot at 12-under overall. Louis Oosthuizen (68) is one of five players at 11 under, while British Open champion Ernie Els (69) is eight shots off the pace in 24th position.