Justin Rose remained in close contact with the lead, just one stroke off the pace more than halfway through the second round at the BMW Championship in Illinois.

Rose, who shot a six-under-par 65 in the opening round, collected an eagle, two birdies and two bogeys in 11 holes on the soggy Cog Hill course.

He was equal second with Australian Aaron Baddeley (16 holes) at eight under, while Colombian Camilo Villegas edged to the front at nine under through nine holes.

Tiger Woods was among those in the hunt in a tightly bunched field, just three shots behind after 10 holes.

Rose made his eagle in unlikely fashion at the par-five 15th, his sixth hole, where he holed an 80-foot bunker shot.

He continued his run by rolling in a 25-foot birdie at the next, only to bogey the par-four 18th for the second day in a row.

The BMW is the third of four events in the new FedEx Cup play-off series.

Seventy players qualified for the BMW Championship, although only 66 started, with Padraig Harrington and Phil Mickelson notable absentees.

The top 30 players on a points list after the BMW qualify for the Tour Championship.

Mickelson leads the standings from fellow Americans Steve Stricker and Woods.

Woods is in the running to win the prize awarded to the points leader after the Tour Championship, even though he skipped the first play-off event.

He has a great record at Cog Hill, winning the old Western Open three times — in 1997, 1999 and 2003.