Vijay Singh moved into contention for his first tour win in four years as he took a one-stroke lead after two rounds of the BMW Championship at the Crooked Stick course in Carmel, Indiana.
The 49-year-old three-time major winner recorded a round of 66 for a two-round total of 13-under 131, putting him one shot clear of first round co-leader Rory McIlroy, plus Tiger Woods and Ryan Moore.
McIlroy's round of 68 included an eagle and six birdies was let down by four bogeys as he dropped level with Woods, who made up a shot to reach 12 under after a bogey-free round of 67.
Lee Westwood produced one of the the best rounds of the day with a seven-under 65 to move to 11 under after two rounds, and his feat was matched by Padraig Harrington, whose 65 left him two strokes further back.
Justin Rose's disappointing 70 left him level with Harrington at seven under, a position also shared with former Open champion Louis Oosthuizen, with Luke Donald one further back on six under.