Published Sunday, 09 September 2012
Rory McIlroy lines up a putt during the third round. (© Getty)
The Ulsterman signed for a 69 as he finished -15 at Crooked Stick in Carmel, Indiana on Saturday evening.
He is level with England's Lee Westwood, with both players trailing frontrunners Vijay Singh of Fiji and US four-time major winner Phil Mickelson by one.
USPGA champion McIlroy - who also won the Deutsche Bank Championship at TPC Boston in Norton, Massachusetts last week - said he is looking forward to Sunday.
He tweeted: "Somehow I turned a 76 into a 69 today! Did some good work on the range this evening... Excited for tomorrow to try and win my 2nd in a row!"
Meanwhile Mickelson equalled the course record with a stunning eight-under-par 64 to surge up the leader board.
Tiger Woods, who was level with McIlroy a stroke behind Singh heading into the third round, slipped off the pace with a 71.
The 14-time major winner, who had four bogeys on his front nine, will start the final round on 13 under and in eighth place.